As the title says, I’ve developed pain that is not sharp, not dull, just nagging coming from under my left shoulder blade. It’s gotten worse in the past few days, I don’t have gas, I am bloated Because I’m about to start my period. I have just started a new birth control.
I’m also well hydrated.

I have something similar; it's like a spasm/pain in the left shoulder area when drinking/eating; my surgeon said it should go away; I hope so!!

You may experience a lot of random discomfort because of your weight loss. A couple of months in I had discomfort across my upper back. Went to my acupuncturist & jokingly said wonder if it’s because all my bras are too big. That was the cause. Bought some new underwear & pain gone. As you lose weight your centre of gravity changes & you start holding yourself differently. Suddenly muscles, ligaments you haven’t used in a while become active. You might get achy hips, lower back pain, etc. I realised I was slouching because my tummy wasn’t there any more to support my upper body. Had to retrain myself to stand up straight.

Or it could be nerves spasming & reorientation themselves after surgery.

Not sure exactly why you are experiencing discomfort - just some suggestions. If it persists contact your surgeon again.

I'm 4 weeks post-op and woke up this morning with a terribly sore back! I have the worst ache on my right side, just below my shoulder blade that I can't seem to stretch or massage out. I took a Tylenol, hoping that will take the edge off. As others have said, I've read that this is pretty normal due to the changes your body is going through so rapidly. Doesn't make it any better, but maybe take solace in the fact that its normal, and you definitely aren't the only one.