Recent onset of leg numbness on left side not relieved with rest but worse w/ walking. No history of back problems but pain in right hip for months.

Glute muscles. You didn't specify where or if the whole leg is numb but it sounds like your glute muscles are tight. Get a deep tissue sports massage or acupuncture to loosen them up. Sometimes the lower back muscles can be involved too. Worse with walking is when when you are engaging the muscles, so it could make send that they would feel worse. Look up stretches too. Do them 2 times a day with good intent.