Before becoming pregnant Id never experienced heart burn in my life ( im 29) and I got this feeling that your talking about for the first time a few weeks ago and I immediately thought it was heart burn. Ive gotten this feeling a few more times and also had the classic heart burn symptoms but Tums seems to help resolve both issues for me!
I do get a similar pain from heartburn sometimes (and I know what normal heartburn feels like) but occasionally it's so bad that I get a new, completely different ache in my chest, shoulder and jaw, which feels more like what I imagine a heart attack would feel like than heartburn. Feels a bit like a lump moving too, and the pressure is bad but it goes away with heartburn treatment so I assume it's heartburn related...
Does it feel like heart burn maybe?