sand in well

My well is 6 years old. Never had more than 5 gpm. Always very sandy. In april of 08 replaced pump, burned up. When it rains or i use a lot of water i get sand like crazy. Had pump-tec surge protector installed so now my pump kicks out. When I have problems i bring in water and "flush out the well". I have to do this twice a year. How can i stop the sand? Several well drillers have said to drill bigger well in same location. Well is 120 feet deep and hit water at 70 feet. This is my second well in six years don't really want to drill another.
Is the screen to big? Well not packed right or am i just stuck with the sand?

A proper well should not make sand. A screen and/or gravel pack should filter the sand from ever getting into the well. If the screen is not right, the well will always make sand. Sand after a rain is an indication that the well was not cemented properly. Need to get a Driller that guarentees his work.

When I bring in water and flush it out it works fine for six to eight months. I was wondering if the screen or gravel pack is getting plugged with sand? I only have about 5 gpm well.

Valveman is right a properly drilled well shouldn't pump sand. I suggest that the next time you flush the well and instead of using water use an air compressor. Be careful because the air will blow water and sand everywhere. Blow it for a time then let it recover then blow it again. After doing this several times let it blow easily and catch some water in a bucket then look for sand in the water. Sometimes over pumping a well with air will allow the coarser sand to pack around the well screen filtering out the finer sands. This will sometimes reduce the sand pumping. If not find a qualified driller to drill a new sand free well.