It is way to early to be thinking that something must be wrong. Nerve pain is to be expected at this stage so early in your recovery. Back fusion surgery can mean a long and slow recovery with it's ups and downs and it can demand some patience. Surgery for back problems is not an sure cure and mutiple surgeries do leave you with scarring which can also be the cause of some of your problems. Right now you need good pain management and perhaps an anti seizure medication like lyrica or neurontin to help you deal with any residual nerve pain. The last thing you need at this stage is more surgery. So please be patient and give your body time to fully recover.