Sounds like your Deltoid/s (three different muscles) are a bit tender from over use. I highly doubt you have any serious problems and wouldn't even consider this a thought, especially at your young age (guessing you are young by the way you write and the questions you ask). It would be an long anatomy lesson if I went into muscles and how they work and there is no need for that here. One thing to know about deltoid muscles is that they are actually a very weak muscle group when asked to do movements they are not used to doing.

In Summary, Just take a few days off, maybe cut back on your poundage and work your way up to the poundage you want to be at. This is JMHO from someone in "medicine "