Help Horizontal line at bottom of reception icon??


Android Question

Hi, i have android 4.2.2. Not sure if any of the coming details are related, but here goes:
- my phone fell today. Looked like all works well. I called, texted etc.
- hours later, i was not able to send a text. Got online with the support, and it got fixed.
- while dealing with that, i noticed a line that i never saw before, as part of the usual reception icon on top of the mobile screen. It appears only when i enter text/call/contacts screens (as far as i can tell, maybe it will show on other places i didnt check).
Anybody knows what this line is? Can i attach a screen picture here?
The support guy said it means probably something is wrong with my phone, due to the fall, and i should go and check it.
Im attaching HERE a screen picture. The icon is marked with red circle, at the top of the screen. You can see the thin blue horizontal line there.