Back of my neck on my right side really hurts and I've had a bad headache for 2 days, is this a migraine?

Could be... Migraine usually have nausea & light sensitivity with them. A cervicogenic headache can occur when the muscles in the back of your neck are tight and pull on the membrane & muscles surrounding your skull. There are other types & causes of headaches that can be concerning too. For a bad headache lasting this long, you should definitely see a doctor.
Possibly. Could be a migraine, but could just as easily be a tension headache. Migraines are due to altered blood flow in the brain. Tension headaches are due to muscle stress/tension/fatigue. If the neck muscles are the cause and there are no other symptoms, it is likely a tension headache. Symptoms that might indicate migraine are vision changes, nausea, sensitivity to light or loud sounds, to name a few.