Experience tightness in chest and pain in left shoulder and elbow when lying down. pain resides when sitting or standing.

Chest Pain -See Doc?: When to see a doctor? How do you know when you need medical help for chest pain? It's not always easy to tell. Helpful simple quiz: http://edition.cnn.com/HEALTH/help.at.home/chest.pain/content.html

Chest tightness: Chest tightness can be a symptom of heart disease but may be may other things such as aortic problems, respiratory disorders (asthma, COPD, bronchitis, lung collapse, infections), esophageal spasms, and muscle problems to name a few. It really depends on the clinical situation and other symptoms you may be having. Depending on the duration it would be worth seeing a doctor.