2 stabbing pains left breast/ left sternum this am.1 pain left breast while reaching 2 hrs later.took breath away.muscular?high anxiety over this.

Pinched nerve: Sharp, stabbing, fleeting pains in the rib cage often are due to pinching of the intercostal nerves which run between ribs. A deep breath may bring on the sharp, shooting pain which lasts seconds only. This is more of a nuisance rather than anything serious. However if these symptoms persist or worsen an examination by your physician is indicated to rule out other causes such as muscular or breast.