My knee clicks every time I straighten or bend it, what's happening?

I've started a exercise regime and have been trying to lose weight, no doubt this is the cause to some joint problems as I've been bending and stretching parts of my body that I have never stretched before! I started this regime about febuary time, I have slipped up a few times but always manage to patch up my plans, they consist of running/walking, swimming, going to the gym and walking.

However, I started doing stretches at the gym, e.g. trying to touch my toes with my hands sitting up, back straight. Finally I am able to do this but since in my right leg, it has began to click constantly. Everytime I walk up the stairs, bend or straighten it, it clicks. I feel it's in my knee-cap, perhaps I pulled a muscle or joint too hard? It's been like this for about 4 weeks at least. There is no pain in the knee itself and it only happens in my right and not my left. Funny enough it hurts a little bit to stretch myself on the left knee, so that tells me perhaps I pushed the right knee too early and too hard.

I haven't seen a GP about it yet, but I thought it would have stopped by now. I thought for a while the sound was distancing a bit, It sounds funny but I thought I broke a little joint at the time and it was evaporating or something! that's what it felt like.

But it's still there, I feel two small clicks whenever I bend/straighten up.

Any ideas on what I can do?