What type of doctor do I need to see?
This list should give you a sense of what type of doctor you may need to get your problem addressed the most effectively. However, you should find out whether your health insurance plan requires a referral from your PCP to see a specialist, in which case you need to see your PCP first regardless.
DISCLAIMER: All definitions below reflect my current understanding based on experience and a bit of research. I cannot guarantee I am 100% correct on everything.
People generally recommended to see at least once a year:
Primary Care Physician (PCP) - your main doctor, responsible for taking care of your whole health rather than focusing on specific parts. They are generalists responsible for catching anything out of the ordinary and referring you to specialists as needed. They are able to diagnose and treat minor ailments such as a urinary tract infection (UTI) or unspecified leg pain, but if they find anything that they don't feel the best equipped to diagnose, they will refer you to a specialist to increase chances of an accurate diagnosis and a targeted treatment plan. Being the cheapest doctor you can see, they also often manage chronic diseases that require you to check in frequently, such as high blood pressure (hypertension) or diabetes.
Types of Primary Care (they all do the same thing; the different names indicate whether there is an age focus):
Pediatrics - kids, age 0-18 (depends on office whether there is a hard upper limit)
Internal Medicine - adults, age 18-65
Geriatrics - seniors, age 65+
Family Medicine - all ages
Dermatologist - skin doctor. While your PCP office can preliminarily identify suspicious skin abnormalities, dermatologists definitely have all the tools necessary to take biopsy samples to confirm/rule out cancerous tissue, and the skill to do so while minimizing chances of scarring.
Ophthalmologist - eye doctor. Deals with your eyeball health.
Optometrist (not a doctor) - Deals with glasses and eyesight. DOES NOT check eyeball health.
Dentist - teeth doctor and first person to go to for any problems in your mouth. PCPs ARE NOT EQUIPPED to diagnose or treat any issues with the oral cavity (teeth, tongue, gums). Technically not medical doctors (MD); dentists go through a separate training and certification process. Dental care is excluded from medical health insurance, so requires separate dental insurance.
Specialists
Cardiologist - heart doctor. Important to have on care team if you have chronically high blood pressure, because that puts extra strain on your heart and puts you at higher risk for heart disease.
Cardiovascular specialist - deals with potential blockages in your blood vessels.
Pulmonologist - lung doctor. Important to have on care team if you are a smoker, or have severe asthma or other breathing issues.
Otolaryngologist - Ears Neck Throat (ENT) doctor. Provides specific imaging of this facial area to diagnose problems and often surgical treatment if needed. Surgeries can usually be done in the doctor's office, rather than an operating room (OR).
Endocrinologist - hormone doctor. Specialize in abnormalities in the glands and organs that produce and regulate hormones, e.g. diabetes, thyroid disease, obesity.
Rheumatologist - autoimmune inflammation specialist. They are experts in conditions that result in chronic inflammation of the joints, bones, muscles, such as rheumatoid arthritis.
Orthopedist - musculoskeletal doctor. They specialize in treating mechanical problems of the musculoskeletal system, such as a fracture, dislocation, sports injury.
Physiatrist - a doctor that does physical therapy, focusing on recovery and improving mobility and function.
Physical Therapist (PT) (not a doctor) - helps identify and correct various body motions that are causing pain or stiffness, and helps you through exercises to restrengthen muscles that are weak.
Occupational Therapist (OT) (not a doctor) - PT mostly for hands, as they focus on helping your fine motor movements to aid activities of daily living (ADL).
Chiropractor (not a doctor) - helps realign skeletal imbalances that may be causing chronic pain, especially along the spine.
Pain Management Specialist - provides remedies that directly treat and manage pain itself, e.g. cortisone injections, but does not address or try to find the root cause of it.
Podiatrist - foot doctor. Often people with diabetes end up needing one because they lose feeling in their feet and find it harder to notice problems there.
Sleep Medicine Doctor - diagnoses and treats sleep disorders, usually through an overnight sleep study. They are the ones who prescribe CPAP machines.
Allergist - will really dive into finding what you may be allergic to so you know to avoid it.
Gastroenterologist (GI doctor) - gut doctor. Specializes in any issues in your digestive system, including your stomach and colon.
Hepatologist - liver doctor. They are more specialized GI doctors who focus on diseases of the liver, gallbladder and pancreas.
Gynecologist - specializes in the female reproductive system.
Obstetrician-Gynecologist (OBGYN) - deals with having babies.
Urogynecologist - specialize in female pelvic floor disorders, can offer specialized physical therapy to alleviate urinary issues.
Urologist - specializes in the male reproductive system, and often surgical management of urinary tract, such as removal of kidney stones.
Nephrologist - kidney doctor. Specializes in non-surgical management of kidney function and diseases that may affect it, such as chronic kidney disease (CKD).
Neurologist - nerve and brain doctor. Specialize in physical abnormalities of the nervous system. They like MRIs.
Psychiatrist - mental health doctor. Responsible for diagnosing and prescribing medicine for mood and personality disorders, such as depression, anxiety, schizophrenia. They are NOT THERAPISTS; their primary tool is medicine, rather than talk therapy. This means they can have poor bedside manner but be excellent at prescribing effective medicine for your needs.
Therapist (not a doctor, cannot prescribe medications) - provides talk therapy, where the treatment is guiding you to talk through your various issues and providing tools for better managing them. Most effective for long-term behavioral change.
Psychologist - doctors who can both prescribe medicine and provide talk therapy, usually more expensive than a therapist.
Wound/Burn Doctor - specialize in large wounds on the surface of your body that require constant monitoring and sometimes specialized treatment, such as skin grafts.
Hematologist - blood doctor. Specialize in diagnosis, treatment and management of various blood disorders, such as anemia and blood cancers like leukemia, in which case they are usually also oncologists.
Oncologist - cancer doctor. The correct person to manage anybody with active cancer, in which case they SHOULD REPLACE YOUR PCP, as they become the point person for managing all of your medical care, including routine blood work.
Infectious Disease Doctor - deals with any contagious diseases with an external origin (meaning you were healthy and then you got sick), especially cases where it is difficult to diagnose the patient from the perspective of any other body system.
Surgeon - doctors who do the cutting, removing, restitching as necessary. Usually specialize in one of the specialties above, e.g. orthopedic surgeon. Those who don't specialize are "general surgeons."
Anesthesiologist - responsible for the drugs that control your consciousness and keep you alive during a surgery.
Radiologist - responsible for interpreting medical images (X-Ray, CT scan, MRI) for signs of disease, often not patient-facing.
Pathologist - responsible for processing biological samples, e.g. labs and biopsies, not patient-facing.
Phlebotomist (not a doctor) - person who takes your blood and other biological samples (e.g. urine, stool).