Hi
 Thank you using HCM.
 I read carefully  your query and understood your  concern. 
First of all I am glad to know that  your 
colonoscopy was normal. 
With regards to 
constipation treatment I strongly advice to my patients to change diet and lifestyle.
So I advice to :
-use vegetables, fruits, salads
-use 2-3 lt  water per day
-use olive oil 1 teaspoon  three times per day
-increase physical activity like walking, swimming, running
-use kiwi, prune 
-avoid unnecessary stress
-use fiber packets 2-3  per day
You will see improvement after  8-10 weeks after lifestyle changes.
 If no improvement than you can use
-castor oil
- sena- fiber
Hope it was helpful to you.
Dr.Klerida