Thank you for the information,
The constant cramping of the left arm and hands can be related to nerve impulses or muscle spasm .
It can be due to pinching of a nerve or its root, in the spine of the neck.
Treatment of pinched nerve consists of rest to the part.
You should not do activities which can aggravate the pain.
Muscle spasm can be due to deficiency of calcium, magnesium, potassium, sodium-electrolytes, vitamins, dehydration, etc..
Poor circulation also can cause muscle spasm.
's disease, Medicines like niacin, calcium channel blockers, diuretics, psychiatric medicines etc can also cause it.
You may try some home measures-
Take plenty of fluid, fruits, vegetables etc.
Take B, E vitamins, calcium.
Avoid coffee, alcohol, tobacco if you take at all etc.
Do regular exercise daily to keep you active. Physical therapy
can also be helpful like stretching of the muscles to release pressure on the nerve.
Before any strenuous exercise you should have adequate stretching to adapt the muscles.
Medications include analgesics
& antiinflammatory drugs like aleve or motrin.
If otc medications do not help then you need to consult doctor for prescription grade medications.
Steroid injections are also used.
In some cases, release of pressure by surgery may be needed.
Imaging studies may be required to see the condition of the spine.
Consultation with the spinal surgeon will be beneficial to assess the exact condition.
Please feel free for any follow up query.