Very scared! Started walking 45min a night 2weeks ago. Feel like I have a charlie horse -right lower calf. No DVT risk but my weight. Cld it be dvt?

Unlikely dvt. Unless there is associated swelling. Most likely muscle strain but if that concerned get evaluated by your physician.
Calf pain. It seems from the history that the most likely reason for your discomfort is due to this new aerobic-type activity. This could be result of the shoe your using. Deep vein thrombosis is unlikely, but if the discomfort continues I would recommend evaluation, firstly by a podiatrist.
Calf pain. You may have a muscle contracture from inadequate stretching or just sore muscles. Dvt can be silent. Even without swelling a simple test can be done. Duplex ultrasound is available for definitive diagnosis. Wear a support stocking until sure.