yeah, i have that too. i always feel like i have to say something to avoid being awkward. the thing is, it's actually quite pointless
. because, the person who you were talking to (in your case, the trainer) most likely does not feel too nervous to make talk, and if they did, then they'd probably be glad there's no conversation hehe.
but despite that knowledge, i still do feel like i have to say something. i think it would be very helpful to find a list of things to talk about when there's nothing else to say that don't appear weird/stupid