Mamacita:
I did a search on "how to pound chicken" here is some paraphrasing of info I found that makes sense to me since I have problems with the same thing..(crime Scene )

Apparently we are hitting it too hard too early. So, here's a good way

Get a gallon sized, freezer weight, zip-lock bag. Cut off the "zipper" of the bag. Cut through the entire length of the closed edge of the bag to form a pouch. Place newly formed pouch on a clean cutting board and lift the top side up to open. Place chicken breast or breasts (just don't over crowd), into the pouch. This action will help the chicken "slide around", so you don't rupture it. Which I believe is how the chicken massacre happens Mama Start at the thickest part of the breasts using the least textured side of the hammer, pound gently using short strokes to get it started. Let the weight of the hammer head do the work. Pound in a slight circular motion and outward to the edge of the meat. Don't beat it to death. Work slow..no need to pummel it

I use either plastic wrap or a ziplock bag to pound chicken but I think the secret I have found is what I am using to pound the chicken with. I use a big rubber mallet that can be found at most hardware stores.

I am a kitchen gadget junkie and this is the best thing I have found so far. I just make sure to wash it really well with hot water and soap and only use it for pounding meat, to avoid any cross contamination.

I have both a wooden and a metal mallet. Using the wooden one, even the toothy side, works best. The metal one pulverizes it!

I've been using one of DH's old nail hammers...could this be the problem...

I aint no cook!!!