The pain in all probability is related to some muscle pulled and possibly skeletal. The movement of your shoulders likely stretches a sore muscle and/or puts a strain on a sensitive area. Doesn't sound serious! Give it some time to heal and doing bench presses may delay the healing process.
sounds to me like you've bruised yourself, this can be sore and painful, i get this when ive carried my baby bfor a while and because its the centre i get worried but i know its my ribs or muscles, if you have pain radiating down the centre i would see a doctor or anything like dizziness, breathless.
I can lift weights like do bench press and stuff like that. But when I like go to tie my shoe and bring my chest together it's hurts