What Causes Crossing Of Eyes In A Child?

My youngest son is 3 years 6 months. On Friday when we got hom efrom daycare my family and I noticed his eyes were crossed. There we no accident reports from daycare. We thought since my 6 year old had just learned to cross his eyes that little brother might be mimicing. It is Sunday his eyes are still crossing. He complains that his right eye hurts. The right eye is the one that is not focusing correctly the other eye seems fine. When covering each eye he can see out of both. He doesn t seem to stumble but has run into the wall a few times. Should we be really worried? OUr other kids eye doctor is just that not a specialist, should we try to find a pediatric optomitrist to take him to right away? Very worried please help.