Hi guys, I had the same problem with my side door buttons sticking in. Sometimes it would prevent us from opening the door at all, not even from the outside.
The problem is with a small white plastic slide inside the button mechanism. It swells or deforms and binds up. Take a half hour with some screwdrivers and a piece of sandpaper & you will save yourself lots of headaches. I made the following fix a few months ago, so I hope the sequence is right.
Sit inside the car & pop off the upper trim piece over the window. Remove the screws holding the trim around the door handle/latch. I think there are some plastic plugs to remove to see the screws. Once that piece is off, remove the screws holding on the latch. You should see the white pieces in question now. Remove them from the assembly & the sliding block is what you want out. Diconnect the springs which are supposed to pop the button out when pressed. Take that block & sand the top & bottom sides (relative to how it is mounted). Those are the sides that I found were binding up inside the white plastic guide.
To sand it, I laid a piece of sandpaper on my workbench and pulled the piece over it until I saw some clearance on each side when assembled. Clean off any dust, give it a little lube & reassemble the whole thing in reverse order. I have not had a problem since doing this a few months ago. This fixed a problem we lived with for over a year.
Good luck, hope it helps you.