Keyboard only types in caps!

I have a white Macbook 13" and noticed a few months ago that my keyboard stopped functioning properly when my keystrokes were typing in all caps, as if the shift key was stuck. I removed the shift keys, which didn't made any noticeable difference. As far as I know, there was no water damage sustained to the computer. Until up about a month ago, I had been functioning with an external keyboard most of the time--sometimes the keyboard would be working fine, but most of the time it would be typing in all caps. This problem would also cause the audio to be shut off on my computer, and I would have to shut the computer down and do a PRAM reset and usually that would fix the audio problem, but not the keyboard problem. Then a month ago, while experiencing an audio issue and restarting the PRAM, the keyboard started functioning properly again and for an entire month there were no issues until today. If not water damage, what could be the issue? I should also note that about three years ago, this computer sustained damages to the screen when it fell off a table and I had the entire body of it replaced soon after. Also, about a couple of months before the keyboard issue started happening, my trackpad stopped clicking. I can still move the mouse, but clicking doesn't work anymore.