Will taking a 81mg. Aspirin a day cause damage to your intestines or stomach. I started on them myself, docs. Never told me to go off of them.

It is possible. but your physician will need to weigh the benefit of aspirin therapy vs any problems as a rule 81mg of aspirin is beneficial and not harmful.
Possible /unlikely. A few people are very sensitive to ASA and may react to this dose but most are not. Whether you should take prophylactic ASA or not should be discussed with your doctor since its benefits are being debated and there are potentially side effects.