Okay, so i'm trying to get used to taking my AR apart. Why is my receiver pivot pin so dam hard to press in. I literally have to take the back of a screw driver and bang on it a couple of times for it to break free. Then, when I go to put the upper back in, I have a heck of a time trying to unlock it from the little spring loaded lock, to slide back in and through the upper. Is this something that will work it self out eventually as the gun is used more? Or is there something I can do now? I sometimes have to take a paper clip to the little hole on the receiver to depress the lock for the pivot pin to go back into the hole of the upper. Sorry for my lack of better description. HELP!

okay, one at a time, not everyone rush in at once here. help?

O.K...I'll stick my neck out.  First..you may have a case of the detent hole in the pin being too deep.  This can cause the pin to go in so far that the taper of the end of the detent goes past the counter sink in the pin.  Effectively locking it up.  I once ran across a batch of selector switches that wouldn't rotate because the pin went in too deep.   Two...get a bigger hammer.  If it won't work now, I don't think it will eventually wear in without some damage to the pivot pin.  Try a different pivot pin.