I have been getting numbness and tingling in my back along my spine. no pain now but had pain in upper back over weekend. could this be caused by a weekend of continuous heavy lifting and standing which was work i wasn't used to? very worried?

Physical activity that you are not used to could result in your symptoms. You may take acetaminophen to help with the pain, no more than 4 g in a day, no alcohol. Warm compresses may help. If it does not relieve in couple of days, see a doctor, Regular aerobic exercise will assist in the long term. Raising core body temperature through exercise strengthens the muscles and make those more flexible.