I'm going to see a neurologist for my migraines, my arm is always tingling numb&painful can the scan pick up the cause of the arm numbness also?

Not readily: Migraine & numb & tingling arm usually have no associated findings on head scans, which are done to rule out unusual & rare conditions. Migraines have no certain known cause. These arm symptoms are likely due to soft tissue problems, which similarly have no accompanying image changes. Chronic muscle tension headaches & thoracic outlet syndrome might be unifying explanations. See an osteopath.

Possibly: Dear serval, most patients with migraines have normal MRI studies. If the cause of your sensory changes is an abnormality of the brain, then an MRI of the brain could find it. However, it is perhaps more likely that you have a lesion in the neck--also called the cervical spine, or in one of the nerves in your arm. A neurologist can help you sort out what kind of test(s) you need.