There cam be several different reasons for this to happen however in the majority of cases there may be a rheumatic problem involved. meaning that you should be seeing a hematologist.
A rheumatologist
Heat near joints can be an indicator of the type of inflammation you get with Rheumatoid arthritis. Suggest it to your doctor, if it is it is important to get it under control.
A rheumatologist is type of doctor that specializes in joint disease. They would know the most about osteoarthritis. However, as this condition is very common, primary care physicians would be able to treat it as well (internal medicine/family medicine).
A doctor who specialises in heart diseases is known as a "Cardiologist".
An 'Oncologist' specializes in tumours.
A rheumatologist
geneticist
Gastroenterologist.
dermatoglist
Cardiologist.
A general practitioner is the type of doctor that treats the largest range of ailments. A general practitioner treats all ages of patients from birth to the very aged.
There isn't a type of doctor who specifically treats doctors.
Immunologist
orthopedic surgeon
treatment for creatine kinase
Neurologist.
No, an oncologist is a type of medical doctor. He diagnoses and treats cancers.