Thanks for your query to HCmagic.
1. The occurrence of retention of fluid and high blood pressure
with your stopping using bicycle may be purely coincidental.
2. A headache weeks after a spinal or general anesthesia
is unlikely to be related to it.
3. Please do not play with your anti-blood pressure medication
like this. A low BP
can cause headache but then it will have certain characteristic patterns, although i do not agree that in your case headache is being caused by low BP. I would like you to continue your medication and see your neurologist
Hope it helps.