Age 42, 6'0" 190lbs Fairly active. (hockey twice a week, daily 30 min walks, at least, with my dog)

I was cross checked to the lower back about 3 weeks ago. At first I didn't notice too much pain, but now when I sit (or bend over/down) for anything longer than 5 mins, when I stand up my lower back hurts a lot. Usually the pain will go away after a few minutes, but other times it will last as a constant ache for an hour or so. Should I be concerned about disc/spine damage or is this most likely muscle issues?