I have degenerating discs in thoracic spine can it cause nerve irritation/pain that radiates to upper abdomen and chest? how would you test for this?

It's possible: A neurologist evaluation and / or an MRI of the t-spine could be helpful.

If there is a: Herniated thoracic disc, then you could have thoracic radiculopathy, which would result in pain wrapping around from your back to sides to the front of the abdomen and chest. Getting a thoracic MRI will inform you if there is a disc pushing on any of the exiting thoracic nerve roots. See a spinal specialist to get evaluated and see if your symptoms may be resulting from your thoracic spine.