Is non linear recovery after decompression normal?

I had decompression surgery about a month and a half ago. The first two weeks were rough but after the two week mark I was feeling better to the point of not needing any pain meds to get through the day. Now, starting last week I’ve been having severe headaches and head throbbing and pain meds don’t help. I’ve been to the ER twice because I suspected a leak but the CT scans come back clear and I’m told this pain is part of the healing process after brain surgery. Has anyone else felt better after surgery and then hit a rough patch this late after?