Weird knee problem

[TheThing]

Hi all, I have a problem with my left knee. It has been going on for around 5 years now so is starting to piss me off a bit. I went to the doctors a couple of years ago but he just told me to go and take some nurofen and it would be ok. He was wrong. The problem is mainly after excercise. After excercise my knee feels tight and is difficult to straighten, it starts throbbing and is generaly uncomfortable. It is quite a strange sensation, however there is no pain. Anyone got any ideas? Im 23 and otherwise in pretty good nick. Doctors and physiotherapists please fell free to chip in

[The_Doc]

Go see a knee surgeon, not an MRI, not a physio.