Joe wrote:

You may be hitting metal in the wall. Can't say for sure. Does the
drill have a hammer / impact mode?

Don't know what your talking about...not that savvy. Never heard of a
drill having a hammer / impact mode..but thats me...and yet, I doubt
it. It is a $100 Hitachi variable drill.

Drills for masonry can either...

1. rotate the bit

2. hammer with the bit (like a mini jackhammer, bits are more like small
chisels)

3. rotate AND hammer a round bit. The hammering greatly increases the
efficiency.

For a casual user, something that will do #1 and #3 are most useful IME.
Harbor Freight sells one for about $30.