The precordial catch syndrome is an exceedingly common yet underrecognized cause of benign chest pain in children and adolescents. The syndrome has a remarkably consistent, characteristic presentation and is therefore easily diagnosed. Nonetheless, it frequently leads to elaborate testing and/or referral to a pediatric cardiologist and can be a source of considerable anxiety for many patients, their families, and their physicians.

Source : Southern Medical Journal (Vol. 96, Issue 1)

Precordial catch syndrome (a.k.a.Texidor’s twinge) was first formally described in 1893, and presents itself as brief, sharp, severe chest pain (usually left hand side) made worse by deep breathing. It occurs at variable intervals, without warning, and typically happens during rest or very mild activity rather than exertion.

It appears to have no link with heart malfunction, and is thought to be completely benign - but as the article above notes, it's frequently mis-diagnosed as a heart problem.

The onset is usually in adolescence, but it can also affect younger children.

The cause is unknown. There is no 'cure' as such, but relaxant medications are sometimes used to reduce anxiety.

Further.info. (GP Notebook)

(Note : 'Precordial' translates as 'before the heart')