This is not a medical condition, it appears to be an artefact due to overlapping of Chest X-ray with X-rays of Cervical Spine.
There is no condition with such a geometrical shape cutting across soft tissues and ribs.
I would also endorse Dr Ashish this cervical spine AP and lateral view long flims including chest.The image with a red button like automated machine seen on AP view but barely visible on lateral view cant be any implant halo jacket? as past histroy of neck trauma seems film artifact as xray machine switch button but how it gets visible on film on illuminator/
You have overlapped two xray films held in a single hand (left hand) and taken a picture with your cell phone against the ambient light of the room door.
And xray is s/o muscular spasm and degenerative changes in a rotated lateral film.
In that case, it could be a Cold Abscess.
But I must point out that taking a photograph with 2 overlapping X-rays tends to confuse most readers, because X-rays are never viewed in this fashion.
You could have sent 2 photos, or made sure the films don't overlap each other.
Disclaimer: All medical case discussions published on this website are not intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek the advice from your physician or other qualified health-care providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website.