Anterior displacement of the xiphoid process may be the result of significant weight gain. Repeated trauma of the afflicted area, unaccustomed heavy lifting, exercise, and perichondritis are, amongst other causes, believed to contribute to the development of xiphodynia.

Why does my Xiphoid pop out?

Calcification of the cartilage associated with the sternum is an accumulation of calcium deposits in that area. The calcified calcium can result in small shards that wear away at the joints, breaking down cartilage. This wearing down of the cartilage can cause the popping sound you may be hearing.

Is it normal for your xiphoid process to stick out?

However, about 5% of people have what is called a “protruding” xiphoid process. For these people, the xiphoid protrudes out of the chest, forming a lump that may look like a tumour. It's totally harmless though and a perfectly natural phenomenon.