I Have Had A Lot Of Pain In My Left

I have had a lot of pain in my left knee. It does not matter what position I am in (laying sitting or standing), it causes severe discomfort. I have not slept more than 2 continuous hours in one night because of the pain. The knee pops regularly and is unstable when I walk. Pain is on the outer part of the knee and upper shin. THere is also pain on the upper thigh bone just above the knee cap. I have been icing the knee and taking Ibuprofen since the pain and discomfort began. What do you believe the problem is, and what do you recommend?