I am in a chapter 7 bankruptcy & I am attempting to short sale my property. What motion & forms must be filed with clerk office.

There is no "motion" that has to be filed - if you are in an active Chap. 7 bankruptcy, you have no legal authority to sell the property at this time. That authority belongs to the trustee. You need to contact the trustee and advise them of the situation and have them contact the bank to give their approval for the sale. The trustee can then file the appropriate paperwork with the court. To be clear, though, YOU cannot agree to anything at this time.

You could file a motion to compel the Chapter 7 trustee to abandon the property. Then after the property is abandoned by the trustee, you could sell the property on a short sale or otherwise.

Another way to go is to wait until the bankruptcy closes (in San Diego its 90 days after filing) and sell the property then. By time you file a motion and get a court order your 90 days may be just about up anyway. And as far as whether there is any reason for doing a short sale is concerned, many creditors including Fanny Mae view a short sale as being less detrimental to your credit than a foreclosure. See link below which set forth the Fanny Mae guidelines.