Why do my strings feel so tight?

I have been playing for years, and this is still a problem I can't solve. Whenever I play, it always seems as though the strings are too tight, even after I tune them. It's even difficult for me to get my fingers off the frets fast, so it's like I'm holding the notes longer than I actually want to. I've learned about adjusting the neck because I thought that could be the problem, but it hasn't done much. The only way I can seem to play good is if I either tilt the pick so I'm hitting the strings with the side of the point, or hold the pick on it's edge with very little pressure (which, either way, always makes the pick rotate, so I spend a good bit of time having to readjust the pick).
I'm generally not into asking questions online, but at this point I'm desperate for answers. I love playing, but this is starting to get me so fustrated that I'm almost about to give up.

Thanks for that help,
Mark