There is a lump on the back of my head, on the right side andit just popped up yesterday and I have been messing with it so it is bigger now. What should I do?

Probable infection. Either a furuncle (deep infection) or sebaceous cyst (which can get infected). Have it looked at. You may need antibiotics, lancing, or both!
Abscess. May be an infected sebaceous cyst with abscess formation. Have it drained or removed by a dermatologist or general surgeon along with antibiotics.
Stop. Stope touching it. If its inflammatory it will go down within a few days. If it persists or gets bigger see your doctor for evaluation.
Family practice . You may have had a small bite or pimple like eruption and due to the rubbing has caused some additional swelling. You could ice it. You would need to see someone if it persists. It doesn't sound emergent however.