Ethel,
Which bar is stuck, needle bar or what? I think you meant the presser foot bar was also stuck but a couple taps freed it up .... maybe???
Anyway, don't tap too hard on it you "could" bend it or change it's adjustments. So, besides the T-F get some heat on it. A hair drier set on high should do it. But don't be in a hurry. Let it soak between heat cycles.
Joe