Sap can come from a natural opening/fissure in the bark, insect feeding or migratory sapsucker birds. sapsucker damage is unique as the bird will "peck' a series of holes like a drill was used. they feed on the sap that flows from those holes. In Illinois, they are protected. Insects are more likely on pines that have been or are stressed. ID is critical as treatments are related to life cycle. natural causes could be from winds for example twisting trunk or branches during a storm.
For a more local and focus response, contact your local Extension office - https://pickyourown.org/countyextensionagentoffices-SD.php