Second set of invisalign trays were tight for the first 2 days and now they seem to not be as tight, is this normal?

I switched to my second set of trays on the 25th February and it was noticeably tight and made my teeth sore for that same day and the next day. It’s the 27th now and it doesn’t have that tightness i felt on the first day and the pain is gone. Is this normal or have the aligners been stretched or bent? I use cold water to rinse and wash them.