Hello..Iam 18 ive been facing extreme stomach pain,back pain and headache at times.. though not regularly.. it is not a common problem but it happens almost thrice a year and sometimes i have a happy period with no pain..why is it so? Is this a problem? Should i be worried about it? Also my medical history is not that good.. i had my appendectomy operation few months ago and also i have kidney stone. Please help!