I have tendonitis in my right shoulder i've had it for about 4 months could it be chronic and if it is what can i do?

Exercises : You are pretty young to develop chronic shoulder tendonitis. Have you had a history of injury? Even so, after evaluation, you can try nsaids, exercises or cortizone (hydrocortisone) injections before you consider anything more aggressive.

Yes, chronic: If beyond 3 months, then by definition, it is chronic. Tendonitis of the shoulder is often initially treated with physical therapy and possible nsaids and/or a corticosteroid injection. More advanced injections or surgery may be utilized, depending on your response (or lack thereof) to the initial conservative measures. It also depends on what tendon(s) are involved- rotator cuff, biceps, etc.