Mole I've had all my life hurts now.?

Sooo.. I have a mole on my tushy, and it's been there my whole life. It's grown with me over the years, and if it weren't for the fact that it's raised and I can feel it, I'd never know it was there (considering the fact it's on my butt). So, over the past little while it's been starting to be uncomfortable. At first a little itchy, then felt kind of like I had a bruise when I sat down, and now it just plain flat out hurts. I don't know if it's borders have changed, if it's changed color, or any of that, I've actually never looked at it. *shocking I know!* So, what I'm asking is.. can this be normal, or should I be freaking out and heading to the doctor? Thanks for your answers in advance :)