Keys Not Working Correctly

A while back, my left shift key stopped working. It feels like it's slightly pressed down and won't fully bounce back up. Regardless of how many times I press the key, the shift function does not work.

Recently my left "a" "s" and "option/alt" keys are intermittently not working correctly. I need to hit the key a few times to get the letter to show up, often resulting in repeated letters: "aaaa". The "option" key is starting to act like the shift key and feels like it's not fully bouncing back up.

I haven't spilled anything on it, but my battery does need replacing. I read that the battery going bad is a possibility, but the battery isn't swollen or anything. I haven't gotten to it yet because I use my laptop almost 24/7 and don't really have the time to swop it out and have something potentially go wrong. But the keys not working is a real nuisance. I pried off the shift key to see if there was anything blocking it, just some dust, so I cleaned it, and put the key back, but it is still not working. Any ideas besides dust that could cause the keys to intermittently not work?