You have not mentioned your child's age. Sudden waking up and crying in a child with cold
could be due to blocked nose due to which he gets a choking
sensation and wakes up crying. Other cause could be ear ache
due to ear infection
which is quite common in young infants having cold. At times Ambrolite- S may lead to sleep disturbances in young children. Try giving him steam inhalations and some decongestant nasal drops if the nose is blocked.
If the problem is persisting, preferably consult a child specialist in your town.