I have really bad lower left side back pain which shoot down my leg with pins&needed and i also have sharp chest pain and numbness in my left arm?

Need to address ASAP: Need to address what might harm you the most quickly. Your chest pain radiating down your left arm describes a heart attack. Take aspirin if not allergic and seek help NOW. Your back and leg symptoms sound more like a herniated disc /sciatic nerve injury. Only after you are evaluated for your heart, a workup for back problems as mentioned should be initiated. Answer is not on internet, call 911.