Is this Acid reflux

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I am 19 year old female and for a few years now, once in a while, I would get this thing at night. So I would wake up and liquid keeps coming up into my mouth from my stomach I am assuming. The duration is about 1 to 2 minutes maybe. It feels extremely uncomfortable and a little bit painful for my stomach (but no burning sensation). It also tastes like water (not sour or bitter). It does not exactly match the descriptions of acid reflux so I am not sure if this is it. Also, I do not consume a large amount of water before going to bed and it usually happens like several hours after I fall asleep. Do you know what is happening?