What is this on my teeth?

[pete]

I just noticed this in my mouth today after feeling some strong sensitivity. What do you think it is? If I touch it with my tongue or nails it feels rough and is like a dent. I don't drink alcohol or sodas or smoke or have too much sugary foods but I do have acid reflux frequently and I do have coffee in the morning on empty stomach.

 

[MattKW]

Nothing to do with acid reflux. This is simple decay, usually from not brushing here adequately, and sometimes made more likely if you've had braces in the past and not maintained your hygiene.

 

[pete]

I have never had braces, have been brushing twice daily using electric toothbrush.
How come the decay is happening so evenly on both the sides on the exact teeth?

What is the solution and does this look serious that needs to be fixed right away or can be done in a few months?

 

[MattKW]

Then there was a period in your life when you weren't brushing so well. It's not going to give you pain any time soon; just get them filled in the next few months.