I have a 2015 Chevy Silverado an I installed after market head lights and now my one side high beam doesn't work

If the functioning side's high beam sub-assembly can be moved (temporarily) to the side that doesn't function (as a test) this should provide the answer as to the new light's functionality or the circuit providing power to this light. (Assuming it worked properly on the other side.) Sometimes, although rarely, a new bulb / lense assembly or component may be defective. If the high beam works on this "good side's" light sub-assembly, then the circuit supplying the power is just fine. If not, then that other newly purchased bulb is bad. If the high beam does not work on the "good side's" light sub-assembly during the test, then the high beam terminal or the wire (circuit) that connects to the bulb needs to be cleaned (along with its ground connection) or the high beam wire checked for voltage. The wire may be broken / "open-circuit" somewhere in its harness. Hope you are successful in your efforts to fix this issue.