Currently i have suffered mild short term memory problem. it has been about 1 year plus. how to overcome it?

Medical & Psych eval: FIrst step is figure out why you are having these mild short term memory problems. You should have a complete physical check up and then followup with an evaluation by a psychiatrist. Once you know what the cause of the problem you can begin to deal with it.

Not sure what: you mean by short term memory. Visual memory, verbal memory, implicit memory, working memory, procedural memory, autobiographical or factual declarative memory ? Is this in isolation or are there issues with other cognitive domains like visual spatial processing, language processing, frontal executive function (judgement, planning, reasoning etc)? What is the presumptive cause ? Treat the cause.