My knee keeps swelling it hurts, I dislocated it bout 4 years ago...What can I do? Its feels like its turing over when I walk! I've used ice an heat

Consult Orthopedics. This sounds like a complicated orthopedic surgery problem. You should consult an orthopedic surgeon. The swelling and symptoms you describe are certainly not normal and suggest a major joint problem. Exam, x-rays, and MRI will likely be needed. Treatments could include therapy, bracing, anti-inflammatory meds, injections, and possibly surgery. You should not let this persist.
Patella instability. It sounds like you may have some chronic patella instability. While ice, nsaids and quad strengthening may help, I would suggest an orthopedic exam she may ultimately require a surgical procedure to correct the problems if conservative treatment is not sufficient to eradicate the symptoms.
Long road. If you dislocated your kneecap, you may have residual instability. Have you done any therapy? You may need reconstruction of a ligament in your knee if you are continuing to have problems this far out from your injury. It sounds like you would benefit from an MRI and a physical exam by an orthopedic surgeon or sports medicine doc to see exactly what is going on inside of your knee.