+1 on Fuji's advice.
You don't really need a separate "shoulders day" (or separate day for any bodypart, for that matter). The shoulders are gonna get grow just fine from flat benching, incline pressing and some overhead presses every now and then. If you're a powerlifter I don't think you need to work OHP as a main lift either as 5/3/1 is set up. Sure, OHP is a good lift to drive your bench up but imo it would be even more productive to work on another cariation of the bench as the main lift on OHP day and do OHPs as an accessory lift. I could be wrong, but I think that replacing OHP as a main lift for the day with pin press, pause bench, board press or even incline bench would do more for your bench progress.
Besides, lots of overhead pressing can be bad on that joint depending on how you're built. Eric Cressey has written som good stuff on that.
Yea, if Eric Cressey saw me he would say I should never overhead press!