Why my engine light came on with codes U1064, P0300, P0171.

Engine light came on in my 2006 Chevy Colorado. Stopped at auto parts store, they hooked up OBD scan, 2 codes came up u1064(lost communication with body module), and p0300 (Random misfire x2). I then took it to nearest dealership.I made an appointment to bring it in the next day. In the mean time the engine light went out. Took it in the next day. They ran another diagnostic test $59.99. They said there was another code p0171 (lean mixture) Then they said they wanted to run a compression test ($105.00)Service manager then came out and said that cylinder 5 was causing the misfire and that the head was warped. It would take 13 hrs. To fix and cost $3450.I did not have it done until I researched it a little. When I left the dealership the engine light was still on. The next day Sunday the engine light went out. Dealership never mentioned any other probable causes, such as O2 sensor, MAF, plugs, wires etc. I decided to try and get an unbiased professional opinion on what to do.
thank you.
Zazz