clicking sound my macbook keeps making?

So I have a 13 inch mb pro (I've had it for about a little more than a year). Today I was moving it from one spot to the other, and while I was carrying it I noticed a clicking sound coming from the bottom. I moved my finger that was touching the bottom of the notebook a bit, and I heard the clicking again. If I poke that area, the clicking sound keeps happening (I'd estimate it's located on the left side, in the middle.) And it's sensitive. Right now as I'm typing this my macbook's on my lap. If I move my leg the slightest, I'll hear the click. I'm not sure what this could be, as I haven't heard this sound before, and I haven't dropped by mb or anything.
Any ideas? I have no clue what this could be..0.o

Fast clicking or slow clicking? Metallic or plastic sounding?

Looking at the component layouts on iFixit I'd suggest it's of the two fans 'catching'.

seems to happen whenever I poke..it's a quiet sound. If I had to pick one it's closer to a plastic sound. (And now I think I hear it elsewhere, but I'm not sure). I poked the right side and then I heard it pop on that left side.

suppose it was a fan catching, would it be expensive/difficult to fix?

It would be a pretty easy fix, I'm not sure what the fans cost though. It would just be a matter of taking he bottom case off taking the fan screws off and unifying the old fan and put the new one in. Look at it on ifixit, it should be pretty straightforward

well that's good at least.
I'm going to look into it when I can. Maybe its covered under applecare...worth looking into I think.

would this be something I have to fix urgently? Because I won't have time to until a couple of days..