To address a few things that have come up:
Cortisone is not a pain reliever; it is a powerful antiinflammatory agent that actually DOES affect the underlying process of injury. But it doesn't always work, particularly if there is ongoing irritation (in other words, if you can't rest the injured part).
There is no surgery for tendonitis. There can be surgical procedures to release adhesions, if you end up with them (rare). Bone spurs and other anatomical problems that can cause tendon irritation can also be addressed surgically, but simple overuse tendonitis is not a surgical disease.
Aspirin is a very good antiinflammatory agent and painkiller, but it has two rather nasty side effects: It powerfully inhibits platelet aggregation (part of the clotting system) and it also causes stomach bleeding. Having an ulcer in your stomach when you also don't clot is not a good thing

Aspirin can also have significant toxicity if overused. The OTC NSAIDs like ibuprofen and naproxen are much more benign, although they can all cause stomach ulcers, and if used heavily over time, can cause kidney damage as well.
Acupuncture is a pain relief modality, and sometimes a very good one, but does not address the underlying process of injury. So, you get pain relief but don't heal any faster.
Inflammatory connective tissue problems like tendonitis and fasciitis tend to be stubborn and hard to resolve, particularly if you don't get rid of the irritant stimulus that caused them in the first place. And since none of us wants to stop slinging dive gear for several months . . . Well, that's why they make NSAIDs!