Check for mites, they make snakes grumpy, but also there maybe a female in you house (snake that is) that may have come into breeding season. It would be an odd time of year, but male boas will get a bit grumpy during the breeding season.
If both of these things are not the case, then you need to look at stress factors..... Is the snake using it's hide box. Does it feel safe. Is there too much light in the cage? is it too hot with the light (did you take an inside the cage temp check or are you assuming that temp is ok because the room temp is ok?) Is there more then one snake in the cage. Is there another animal in the room (rabbit, cat, ferret?) all these things could change the attitude of the snake. Or it may just not be feeling well and is starting a difficult shed cycle?
good luck
Jim Hopkins