Hello!
I am sorry to hear about your headaches. I also struggled with this question of rebound headaches.

I had migrane/ tension/ cervicogenic headache (neck/whiplash) constant for years. Very painful and I know a lot about headaches After a long time of taking Tylenol Extra strength every day I decided that i may be having a rebound effect.

The doc said that no, otc meds such as ibuprofen and tylenol do not cause rebound. 'Heal your Headache' the book also listed those as the non rebounders. (I do not believe that this book is all good, only some parts).

I decided to experiment and stopped the tylenol. It was very painful. Yes, I did notice my pain went down around week two but only in the slightest. Maybe a number or half. But there was time that I said... This is the rebound effect!

So, maybe a slightest effect but if your are suffering from the pain I would say not to worry about taking those pills. But! other narcotics do cause this, hopefully get off of those as soon as possible.

Take Care!