What other problems could cause tingling in left heel when body temp rises besides ms. all mris negative for ms just t7-t8 herniation and l. stenosis?

Likely L stenosis: With limited information available I suspect the back problems are involved in your symptoms. A nerve conduction study might be needed in order to better explain your symptoms. Do discuss with your physician in order to pinpoint the cause for your symptom.

Not likely: Not stenosis and not this kind herniation you have, can be reason for this feeling. This peripheral neuropathy need further investigation. Good luck.