How long does it take for a concussion to heal? can you have on and off headaches in that length of time?

Up to 6 weeks: In general, the symptoms of concussion may take up to 6-8 weeks to go away. Intermittent headaches may occur as may other symptoms like dizziness, nausea, sensitivity to light or sound, difficulty concentrating. The overall trend however is one of continued improvement. If the headaches or symptoms persist you should have an evaluation by a physician.

Head concussion: It depends on the severity of the concussion - the more severe the longer the time to recover. In a severe concussion it can months for the symptoms to resolve and in some cases even up to a year.