Upper back pain, below my shoulder blades, kind of like in my upper ribs

Ally • Nurse 💉 Wife 💍 Prego w/ 💙💜 twins

Hi guys so I'm 4 weeks and 5 days pregnant.. and as soon as I started running today at the gym the pain in my upper back was horrible. The pain is like under my shoulder blades and almost feels it's in my ribs. I dont know if it's gas or what but it hurt so bad I had to leave the gym. It did feel a little bit better after I stretched and am wondering if I pulled my muscles I just dont know how. Any one else experience this??