If your caramel is not fluid enough for you and you are not cooking it at all after adding the cream (i.e. caramelizing the sugar to desired color/temp, deglazing with cream/butter/etc. off the heat, and then using it), you don’t have enough liquid in your caramel. Putting it back on the heat will only make it stiffer as you will be cooking out more water.
Are you starting out with a recipe for a chewy caramel candy or are you starting with a recipe designed to be a sauce or bonbon filling?