Resting ecg shows narrow and fairly deep inferior q waves but stress test is normal. what does this mean?

Not much: Q waves may indicate previous scarring from infarction or other process or may be completely normal or from a conduction abnormality (hemiblock or accessory pathway). Was the stress test with imaging? If the imaging was normal and the ECG is otherwise normal, the Q waves are probably meaningless.

Diaphragmatic : Deep narrow q wave in the inferior leads may be due to diaphragmatic motion!

Ecg: Sometimes thickening of heart muscle is a reason , a lot of times considered normal , best to ask your doc or consult one of us