I'm A 57 Yr Old Female Who Has Been Experiencing

I'm a 57 yr old female who has been experiencing pressure on the left side of my chest. Not severe pain or preventing me taking a full breath but it has been expanding. It is now expending to my arm. I noticed the pain this morning and it felt like maybe a rib or two were out of place. But now that it is expanding, it concerns me. Thanks for your response.