Brief Answer:
Few more details are required my dear.

Detailed Answer:
Hello nad thanks for choosing 'Ask a Doctor' service for your query,
Have seen your details and appreciate your concerns.
As colonoscopy is normal inflammatory bowel disease and other pathologies are ruled out.
As pain involves sides there is a possibility that it could be due to dyspepsia which involves severe bloating belching and acid peptic disorders.Dyspepsia is an umbrella term which covers all of them often symptoms of irritable bowel syndrome also.
Generally when a patients digestion is poor then the food starts to stagnate in gut as a result of which a part of the acid secreted by patient gives him/her reflux which may present as heartburn called gastritis.This is a possibility if pain involves right side(gall bladder has already been ruled out in your case).However if pain involves both the sides or predominantly left side then due to improper digestion food starts stagnating inside your gut releasing toxic gases on fermentation which compresses the intestines.On top of that colonies of bad bacteria's and yeast may form causing inflammation along digestive tract which presents itself as pain which may radiate to back.
I have few questions,
How are your anxiety levels and sleep cycle?
Are you an anxious person a sort of perfectionist?
Do you ever feel constipated?
How are your bowel habits?
what is the usual color consistency of your stools?
Have you ever tried Pantoprazole or activated charcoal tablets for bloating?
Any history of acid peptic disorder?
Can you pin point the exact location of your pain or is it Generalised in nature?
It usually involves right side or left?
How are your food habits?
Need few more answers to guide you properly.
Waiting for reply.
Thank you!

---