Why does the corner of my toenail hurt?

I've always had a problem with the edge of my toenail hurting but lately it's been hurting alot more. It only hurts when I bang it against something. I give myself pedicures all the time and I thought if I tried pulling whatever is wrong in that area, that it'll feel better...but that never worked. Then I noticed my toenail smells a little. What is it or what should I do?