Assuming you have already ruled out body pain and ill-fitting tack as the source of grouchiness, some horses never get used to being stalled all day, and will just be grouchy until they get turnout time. When you pull her out of the stall to ride, give her time to stretch those unused muscles before asking her to get down to your focused, serious riding work.
If my boy has been stalled for a few days of bad weather, I'll walk him up and down the barn aisle for a minute before making him stand tied for tacking, then let him get out any pent up energy on the lunge line before I hop on. He won't exercise himself if I turnout in the covered arena, either, so I have to make sure he's moving those muscles. Even if I don't have time to ride, I do my best to at least pull him out of his stall for a handwalk every day he is stalled.