I have rotator cuff tendonitis w/ impingement and constant pain then every few weeks swells up and bruises and is extremely painful, what can I do?

Many treatments . Rotator cuff tendinitis and impingement can be treated with therapy and antiinflammatories. If that fails a steroid injection can help. If nothing works a shoulder arthroscopy may be needed.
Several guidelines. Have you checked with an orthopedic sports medicine specialist? You may require oral medications, a cortisone injection and physical therapy. Surgery is a last resort for these types of problems.
Physical therapy. Pt is the best place to start for rotator cuff impingement. The bruising is unusual and should consider an MRI if not improving.