As I have been resting from my concussion over a year ago, I have not exercised regularly at all. I went from an extremely high activity high calorie diet, to an extremely low activity and high calorie diet.

Naturally I put on literally 20 pounds in the first month, then changed my diet. The other day I tried going on an exercise bike (I haven't had any symptoms besides headache and ear ringing in a few months), only for 5 minutes with not too much head movement, and I have a huge headache now.

Could just blood flow after a year of not exercising cause a headache? Are there any other low impact exercising regimens that will help me lose some of the weight I put on?

I have an alarming family history of heart conditions so this is really quite important.