.....My hermits do the same thing, a couple of days ago they were pulling each other out of the shells and climbing on each other?!?
and they are still alive and doing good ( wonder if I will have little hermits soon..)
Your hermits may also kill each other looking for shells. That is what they are doing, so I would strongly suggest additional shells if you don't have any already.
In the wild, hermits will commonly aggregate and exchange shells and such. Always good to have plenty around to be sure, and prevents them killing snails for the same purpose. Its possible, but not incredibly likely, to get baby hermits...