Yep, normally an infected ingrown hair!! They bloody hurt! Sometimes they will raise a head and you can pop them like a pimple (that hurts) or they will go away eventually.
Yes i have experienced it these past 7 years, it could also be an ingrown hear, an infected hair folicle, or also a clogged pore... shave about 3 times a week instead of every day. And use hypoallergenic deodorant. Also when you have days in between shaving and your hairs start to grow, look closely at them, find the really thick ones and tweeze them out, or the ones that look like there is a bump...right now let your hair grow a little and tweeze all the ones on that bump.