Creating ASP.NET controls dynamically

I want to create ASP.NET controls dynamically on page behind code and retrive them success fully on post back. Items what clicked is from a user control. A link populates several groups from database. This group will let me know items belong to this group will be a check box list or radio button list, or dropdow list. So a page should be able to create several page behind controls based on number of groups from database and then assign values to them. Till this part every thing appeared simple. Now when user selects several items from this dynamically generated controls, i can retrieve only first type control value>? I can retrieve other controls but it does not reflect user changes on post back? is there a reason for this behavior ? Anyone can please tell me a solution to achieve this?