Can fibromyalgia cause hot&burning sensation in the left shoulder&neck at the same time with cramps. Does it cause throbbing in diff. Body parts. Help!?

Not really. Fibromyalgia is a whole body malady characterized by aching pain. If you have symptoms specific to a region of the body (arm or leg), you should see your doctor to find out what is causing them. It would be unusual for fibromyalgia to cause regional symptoms.
Maybe. It can, but the shoulder/neck issue could also be a different problem involving pinched nerves or else so an evaluation by your physician is certainly indicated.