The other thing to note is, that unless you have a footbed to stablize your foot, your foot may just spread into the extra space created by streching the boots. In my shop we dont strech boots unless there is a custom footbed in them. Its just not worth it. Often the footbed can mean you dont need to alter the shell.
This is what I would have looked at. If you have one, have a fitter see if it is supporting your foot corectly, maybe it needs stiffening. If you dont have one get one.