Stepped out of my van felt a pop in my calf now hurts like charlie horse pain is intense only when put pressure on it?

Tear of calf muscle. This is most likely a partial tear of your calf muscle (the gastrocnenius) -- initial treatment would involve rest, ice and antiinflammatory medicine along with gentle stretching of the calf -- this type of injury sometimes benefits from physical therapy as well -- if pain does not improve, it would be wise to schedule an appointment with your primary care doctor.