I'm experiencing frequent throbbing headaches after having a tummy tuck.

Hello, the majority of my patients do not have persistent headaches many days after their surgery.  I would recommend contacting your surgeon or other physician to discuss your problem and possibly get some relief.

Pounding headaches could be a symptom of blood loss or a reaction to your pain medication or just generalized dehydration.  I would not think it is related to your garment being too tight.  See your plastic surgeon for an evaluation and testing if needed.