Efficacy and Safety in the Combination of Celecoxib / Pregabalin / Vitamin B for Low Back Chronic Pain

Researchers will compare the fixed-dose combination of Celecoxib/Pregabalin/Vitamin B versus Celecoxib + Vitamin B versus Pregabalin + Vitamin B for chronic low back pain. The adverse events related to the interventions would be registered in each follow up visit. Participants will: * Be randomized into one of the 3 intervention groups (A,B,C) once a day for 12 weeks * If needed the dose could be escaleted twice a day. * Visit the clinic at weeks 2, 4, 8 and 12 for checkups and follow up