New weird symptom this morning

Was woken this morning by a new, odd symptom. It feels like I've done a few hundred situps for my upper abs. It's an aching, sore muscle feeling just below my sternum that wraps around my torso. It's like there is an imaginary belt wrapped tight around this area. It aches and throbs and has NOT released yet. It's not chest pains or anything like that, just a sore, aching feeling and pressure.

Can't really describe it any other way.