I Have Pain In My Left Arm And My Left

I have pain in my left arm and my left leg often. I also notice a little weakness. I am active and healthy otherwise. I have also noticed a red rash that pops up often. Generally, I have no allergies. Could it be MS? I would like to see a specialist or have some tests run but don't know what kind of tests need to be run or what kind of specialist I need to see.