Thanks for your question.
This might be behavioural, however according to a study if no cause is found then milk allergy may be suspected and tested for by your doctor. But you may consult a child psychologist to know whether this is behavioural insomnia.
Colic may take in some case up to 8 months to stop.
When did the colic stop? Which formula are you using?
Changing to a different type of formula called hydrolysate infant formula (such as Nutramigen 2 with LGG) if your baby is allergic to cow's milk or has a milk intolerance may help.
Some behavioral changes that may be helpful are:
Children need to be taught how to fall asleep in their cribs or beds and return to sleep during the night with minimal parental intervention.
Graduated extinction is an efficacious method that can be used by parents.
You must place the child into the crib or bed before she is fully asleep to allow your child to develop an association with the surroundings that will be present when she awakens during the night.
If there is nighttime crying, you should only make regular checks on the child while she is crying and gradually increase the time between the checks and thereby decreasing the frequency of checks.
Don't hold or rock the child during the checks, as this will reinforce the crying and the need for your intervention to return to sleep.
This way the child is reassured of your presence, and without any intervention the child will learn self-soothing techniques and often will accept that she is safe, her mother is near, and that she can fall asleep without help from you.
Yes it does. Also the learned behaviour of nighttime sleep will also be seen for the naps. So gradually start this method.