I have knee pain and I've tried motrin, ibuprofen, tylenol (acetaminophen) etc. And none of it helps. Is there anything else that I can take?

See Dr. Over the counter meds like glucosamine or fish oil likely won't help either. You need a formal DX to know what to do next.
Visit your doctor. Knee pain has many causes. Pain relief does not equal cure. You need to have your condition evaluated and see if you need physical therapy or surgery to cure the underlying conditon and to relieve the pain.

Related Questions

Severe Knee pain on a knee I injured 10yrs ago. Hurts to leave it still and move it. Tried Motrin and Tylenol (acetaminophen) for pain. Slightly swollen behind knee?

See details. Then see an orthopedist or rheumatologist and have the knee properly evaluated.
Get it checked., This could be lots of things. Given the chronicity of this problem and your symptoms, you should see a doctor for an eval and X-rays.