What Causes Central Ribs Pain Intermittently?

Hi there, the past few days i have had unbearable pains just below my ribs in the center... I believe it may be my liver but not too sure. The pains last about 5 seconds, extreemly painful but when the pain stops I'm fine, back to normal.... it stops for a few minutes and does the same again, this contunues for various time spans but then can have few hours break till the next batch starts. Tends to be worse at middle of the night & early mornings.. any ideas?