Hi Ian! Yes, I get stabbing pains in my chest, ribs and back (near my shoulder blades) often... several times a week, sometimes an all day nuisance! I get lidocaine shots from my Pain Management doctor and I take gabapentin. Gaby doesn't seem to help much with transitory stabbing pain. The shots do.

I had stabbing pain between my shoulder blades recently. My chiropractor adjusted my neck & for TMJ.

If it hurts to breathe that could be costochondritis , ibuprofen and rest should help (heat or cold compress whichever you prefer could also be good).
I do have similar pain to yours but mine is not typical costohondritis pain, 0.25-0.5 mg Clonazepam eases up the pain, takes care of the stabbing .
After 1 year of struggle I did have a chest CT with contrast to rule out my biggest fear of lung cancer. It came back all clear.
Considering you have GAD you probably walk around, sit, even sleep with super tense muscles, try to consciously relieve muscle tension and relax (drop shoulders, even jaw muscles etc.), it does help. Progressive muscle relaxation exercises makes you aware how terribly we have the tendency to tense up all the time subconsciously causing muscle exhaustion and the whole nine yard as you can imagine. I have GAD it is awful, it is like a separate entity in me, it always has some unpleasant, unexpected surprise for me. Your GAD is playing games with you most likely, but as you said you are concerned, go ahead and ask your doctor for a work up, just for a piece of mind, then next time you know for sure its nothing serious. Hope you feel better soon!

I was actually diagnosed offically with GAD after taking lyrica for sciatica. I realized how bad and significant my anxiety was once it had decreased from the medication. I know some people can have quite unpleasant side effects. But for me, it has changed my life for the better in regards of fibro and anxiety.

Ive had this excrutiating pain in my ribs under my left arm and between my left ahoulderblade and spine for years (in addition to my general rib pain). It has been so bad at times it hurt to breath, move and function. The only thing that helped me (and actually worked) was when I started 60 mg duloxetine a day with lyrica. Fortunately i havent had any negative side effects from these meds, and the lyrica significantly helped my GAD.