Headache and uneasiness in the head after gall bladder removal

My dad had undergone a gall ladder removal laproscopic surgery few days back. Before the surgery he had bad taste in mouth, pain near abdomen and headache. After the surgery, he fully recovered from all the problems right after 2 or 3 days. The op was a neat and successfull one. He is not having any pain now or bile kind of taste in mouth . 

But, in the evenings or morning, one day or other, he is getting discomfort in head and headaches. I am really worried since we are clueless. Is it going to wither off just like the other issues? or is there anything else I should look for? When could he fully recover from his headaches? What might be the cause for it? please help us to get cleared

Hi 

the fact he had a headache before the operation rules out the operation causing it . Or the anaesthetic..

stress causes headaches, migraines , back problems , endless list if it keeps up he should go to gp.. 

I think he should see a doctor asap it could be his blood pressure is high due to stress of the operation.

Get him checked out but, it could simply be he's not getting enough fluids in him or if he's taking painkillers it could be that, Paracetamol is know to give some people headaches. I had dreadfull headaches because being sick all the time I'd become dehydrated.