So I finally got this fixed and it was indeed an hardware issue. I took it to the Nokia care center and told them about the issue. They said it was a simple fix and changed some padding under the button. It seems to be working fine, have been using it for a couple of weeks.
Also told them about the photo and song duplication bug, they said it can be an issue with the memory card (I was using a very old class 4 card, they recommended a class 6). I decided not to use a memory card and see if the issue exists if photos are stored in the internal memory and till now it seems to be working alright, so I think it is indeed an issue with memory.