I am not sick but almost vomiting from gagging and burping,some exess flem, any ideas?

[James J]

hey as of few weeks up to month, been gagging alot, not sure why, and almost vomiting, and having alot of flem coming up. I not sick, i do martial artis trainng and i notice afer i train it goes away, it usualy accures just during the day or moring, or after i eat... i notice after i eat this happens alot! what could it be? sometims i feel air in my stomach, but i dont know where its coming from.. burping alot to..