I was diagnosed with short term memory loss at age 28 or 29 years old but the neurologist couldn't say what causes my memory loss and might never know . can i get a second opinion to a different neurologist and could he find out what is causing it?

You can seek as many opinions as you wish and may never find the information you seek. The issue becomes were you wired that way from birth, or did some event or affliction cause the change. I would consider doing another at a medical school or large specialty center where they do research. Sometimes they just cannot find the answer.

There is always an explanation as to why disorders occur in different people, but sometimes it is difficult or impossible to prove an actual diagnosis. Suspect that your memory issues may be associated with a learning disorder, and date to events occurring in utero or around labor and delivery. There may have been some hypoxia at birth. Yes, find a medical school neurology department.