Painful edge of left rib cage below sternum. feels like there's some pressure; deep breaths, bending, & moving are uncomfortable. tender to touch.

Pain location: gives the likely etiology. Cannot say in your case without an exam but, tender to touch, on the outside, implies a musculo-skeletal condition

Costochondritis: Many of these symptoms together can point to costochondritis, a benign inflammation of the bone and cartilage of the rib cage. It can be treated with limiting exertion, anti-inflammatories and warm compress. Less likely, there can be more serious concerns. Should you have difficulty breathing, inappropriate sweating, or leg pain or swelling, seek out immediate medical attention.

Here are some ...: What you described most likely resulted from some irritation to your regional muscles, joints, or nerves. To confirm such, please collect & bring the detailed info on the onset, degree, duration, interval, evolution, progress, & resolution of these pains and their potentially related discomforts over time to Doc for analysis + physicals + tests as needed so to deduce Dx for Rx / care / counseling