I am having pain on left side lower back, especially when i push on it. do i need to see a doctor right away. i have no burning when i urinate.

Low back pain: Low back pain is extremely common, and usually represents just a muscle strain/sprain. There is no need for an urgent doctor visit; give it a week with Ibuprofen treatment to see if it doesn't get better on its own. Other causes include a slipped disk w pressure on a nerve, fibromyalgia/fibrositis w subcutaneous cysts, or (rarer) intrinsic vertebra problems like infection, fracture, tumor, etc.

Maybe: New onset flank pain without any overstrerching or injury can be pathological such as a kidney stone. But then again, common thing common can be just a strain to the back.