Have excruciating pain in upper left arm. had tennis elbow with cortisone shots previously, advice?

Upper arm pain: It really depends on the precise location you are referring to. Tennis elbow causes pain just below the elbow joint and is usually injected with cortisone. If you are saying you have pain in your upper arm, this is not likely to be tennis elbow. Depending on the precise location it could be tendonitis, arthritis, impingement, or nerve injury.

Same thing?: Tennis elbow pain is typically oveeouteraspect of the elbow, not the upper arm. Pain there makes me think of other causes, such a deferred pain from the rotator cuff. I recommend an evaluation with a shoulder/elbow surgeon.