Doctor says "everything is normal" with the MRI and my blood tests. He recommends I take an Advil prior to working out to help relax the muscles to prevent the headaches. Tells me he will send me to a neurologist if the headaches come back.

So I went back to the gym a couple times this past weekend and pushed myself relatively hard. No headaches or anything...felt like my usual self. Of course now I'm sore as hell after my month off, but my strength is still up there right were it was when I left off. Weird.