There can be many reasons for back pain.yes the pain may be aggrevated after the stretch depending on which muscle you streched and if the postural alignment was good  .its advisable you visit a physiotherapist who can assess you .after knowing the cause then we can conclude what exercises and which strerches is good for u . Along with stretches strengthening is very important. And as you said its an acute pain please do it under a preofessional supervision or else the pain will aggrevate