Pain on bottom of big toe when stepping or pressing on it. Almost feels like a stinging pain. What could this be?

Sesmoiditis. This is called sesmoiditis. There are two pea shaped bones on the bottom of the big toe, and with certain activities and shoewear (i.E heels), these bones can get inflamed. Usually gets better, but takes a long time. An easy solution is to pick up something called a dancer's pad that you stick inside your shoe to take pressure off of the bottom of the big toe.
Several. Pain in that area can be many things..Sesamoiditis, joint capsule pain, tendonitis, etc. The key is to identify the apex of the problem...A podiatrist can help do this and get you on the way to full pain free activity.