You are right that I think you should see a doctor
! Persistent muscle cramps like this definitely need to be evaluated, and your primary care doctor
is a good place to start.
Cramps that come on out of the blue like yours could be caused by a number of different things. Shifts in the electrolytes in the blood are a common cause, and your doctor will probably want to check your levels of potassium, calcium, and other basic chemicals. Similarly, problems with the thyroid gland, with iron deficiency anemia, or certain vitamin deficiencies could also be associated with cramps. These problems could be indirectly related to smoking or heavy alcohol use in a number of ways. For example, excessive alcohol consumption could lead to chronic bleeding
in the stomach, causing anemia. It could also vitamin deficiencies.
The skin rash may also be related to your symptoms, although it may also not. Certainly vitamin and iron deficiencies, as well as changes in the thyroid gland, can all provoke changes in the skin, including various rashes.
Your doctor will be able to give you a thorough checkup and help you determine if your symptoms are related to each other and what the next steps in treatment need to be.