Inclusion Criteria:  Age between 18 and 65 years Non-specific neck/low back pain for the last three (3) months before the first session.  Exclusion Criteria:  Previous surgery in the areas covered by this research (neck and/or low back) Red flags: Cancer or tumor, fracture... Scoliosis or osteoporosis Neck or low back pain with radiculopathy symptoms Central nervous system involvement Fear to manipulation Neck pain associated with whiplash injuries on the last six (6) months Pregnant women Not understand, write and speak Spanish fluently