Penile erections can occur in all age groups. Even newborns can have penile erections during certain stages of sleep. So it is not unnatural for your child to have penile erections.
Painful and sustained erection is called priapsim and is seen in certain conditions like Sickle cell anemia
. There maybe no association of this condition with circumcision
performed at the age of 2 years.
However, before we arrive at any diagnosis it is better to get a complete evaluation of your child's problem with a Pediatric Urologist
Remember these conditions need to be addressed at the earliest so get an appointment soon.