Your symptoms sound very much like my husband’s situation. Two years ago he developed burning in his stomach and this feeling of tightening or muscle spasms in his stomach/chest area. An endoscopy showed an ulcerated area in his stomach from daily aspirin and evidence of a hiatal hernia.
His stomach has now healed. However the spasms, which felt like a band pulling around his ribs or a gripping feeling in his stomach area, persisted. They were relieved somewhat by taking FDgard. It’s an over the counter med recommended by his gastroenterologist. It’s safe to use as it’s basically oil of peppermint. It seems to be a common med suggested for people with a hiatal hernia.

Because the symptoms didn’t go away completely, his gastro-doctor also prescribed a very low dose of an anti-anxiety med, Zoloft. He’s not prone to anxiety but the med works as a relaxant for those muscles. 100mg of Zoloft brought significant relief. Added to that was 5mg morning and night of Buspirone. That was the winner long term. 100% of his symptoms are gone.
Although his doctors didn’t suspect a heart issue, prior to going on those meds, my husband had a calcium score test run and a physical to rule out any heart issues.
I hope this might help you or give you a direction to follow.
Have you had a physical to rule out any heart/lung involvement?