Kinda tough to tell from your photos. If it has a smooth skin, but there are patches where that skin looks battered, and as a result, has a rough texture, rather then the smooth texture elsewhere, then it's likely a hammerstone, since you said you found lithic flakes associated with it. Your photos are just enough out of focus to make it tough knowing if those bright areas are battered patches.
Looks like a multi- use tool to me. A natural stone that was used for hammering (the rough end) and as a working surface (the flat side with roundish divot worn into it).
The depressions are sometimes hard to illustrate in a picture, wetting the depression before taking the pic. usually helps.