Last week i think i pulled a back muscle and it is still bothering me. how long should i not stress it? i.e.working out

It can take up to: 6 weeks to fully heal. Pay attention to proper body mechanics, you can take NSAIDs if you have no contraindication to this like ulcer history etc. (ask your doctor), avoid strenuous activities till pain starts subsiding. No heavy lifting until then, if symptoms worsen, or persist after 4 weeks, or if you start experiencing weakness, numbness or tingling, then go see your doctor.