HI
Greetings from Dr.Divakara.P
Thanks for posting your query. 
      I went through your query and definitely I can help you . But I need more information on your problem . 
1. Since how long you are having this problem ? 
2. Is your bowels loose or normal? 
3. Is there any problem in passing urine too? 
4. Is there problem in having Erection ? ( if you are male )
5. Did you had any trauma to back anytime ? 
    This problem could be either due to 
malabsorption or neurological . If it is malabsorption then your motions will be loose . In that case we need to evaluate for the cause of mal absorption . 
  If it is neurological your motions will be normal and in that case you will require a different set of tests. 
Kindly revert back to me soon with details asked . 
Regards.