Is it normal for front teeth to occasionally hit on s sounds while speaking?

It is not normal for your teeth to hit, but this is something that you may be able to prevent as you get used to the adjustments that have been made in your mouth.  Your are options are as follows: 1) Try going back to the dentist to have your bite slightly adjusted to prevent this hitting.  2)  Try giving it a few more weeks with no adjustment to see if you improve naturally.  Good luck and I hope this helps. Follow me if you have more questions.Sarah Thompson, DMDReal Self 100

if u feel any pain in that area [means high point / touching upper and lower with heavy force],  in that case visit yr orthodontist [u have a permanent retainers so tooth movement is not possible thats
why, in removable retainers minor changes occurs as per normal function].
otherwise no need to worry.

Your teeth really shouldn't hit. It sounds like having a simple adjustment on your retainer would probably solve the problem. Call for an appointment and they should be able to do it quite quickly and easily