Hi, I don't have any advice but my son has started doing the exact same thing. He is 8 1/2 months old and up to now solids presented no problem. I am trying to introduce foods with a bit more texture. Some times he is okay but every once in a while he gags and throws up. After he throws up he is perfectly fine so I don't suspect any stomach problems.
Sorry I have no solutions but you are not alone!
Sara, mom to Sam