Dr for mole?

I have a mole on my back that is getting bigger than it used to be and if someone touches it, it hurts a little. Laying in the tanning bed or being in the sun a long time with my back facing the sun makes it burn. What should I do? Does it need to be checked by a dermatologist? Am I just overreacting?

UPDATE: it is still circular but I'm really worried about the size of it and the burning. But I didn't wanna go to a dermatologist for them to think I'm silly for worrying.

UPDATE: I don't go to a tanning bed very often, but when I do it burns.

UPDATE: I have not been to the Dr about it yet.