Worst heartburn?

I woke up at 12 am with what I can only call heartburn, but it felt like a shooting fire starting from the base of my sternum going up into my throat and branching out a little in my chest. It felt tight and SO uncomfortable! I got Tums and laid down and finally got some more rest once I laid extremely still on my left side. I feel some tightness now, just a little uncomfortable when I take a deep breath. Could this still actually be heartburn? I had it with my first pregnancy and it felt more related to my stomach then 😣 only 4DPO