Hi, hiccups, or hiccoughs, are involuntary sounds made by spasms of the diaphragm. They are usually harmless and resolve by themselves after a few minutes. The cause of hiccups is often unknown and there may be no apparent trigger. Various triggers, particularly those that cause pressure on the diaphragm, are known to prompt an attack of hiccups. Certain lung or liver disorders can promote hiccups. Sometimes a cause is never identified when it is referred to as psychogenic. This is a probability as you have had them for prolonged duration. Regards.