Despite the availability of various specific treatments, most patients with chronic pain (CP) consider their pain problem as undertreated. Recently, multiple sclerosis (MS) patients who were given an intensive 3-day social cognitive treatment with the participation of support partners experienced lasting improvements in health-related quality of life (HRQoL) and self-efficacy. In this study, a similar intervention was given to treatment-resistant CP patients with stressors, relational problems with support partner, and distress, anxiety or depression. Before and 1, 3, and 6 months after the intervention, patients completed the Euro-Qol 5 Dimensions 5 Levels (EQ-5D-5L) and Impact on Participation and Autonomy (IPA) questionnaires (primary outcomes), and the Survey Of Pain Attitudes (SOPA), the Four-Dimensional Symptom Questionnaire (4DSQ) (distress, depression, anxiety, and somatization), and Visual Analog Scale for pain intensity, whereas the support partners completed the Caregiver Strain Index (CSI) questionnaire. Differences between baseline and post-treatment were tested via paired t-tests (significance level 0.05). Of the 39 patients who were included, 34 (87.2%) completed the 3-day treatment. At 1, 3, and 6 months, improvements were seen in EQ-5D-5L-Index (+40.6%; +22.4%; +31.7%), Health Today (+61.8%; +36.3%; +46.8%), Control attitude (+45.8%; not significant [NS]; +55.0%) and decreases in IPA-Problems (−14.8%; NS; −20.4%), Harm attitude (−18.9%; −15.0%; −17.7%), Distress (−17.7%; −31.8%; −37.1%), and Depression (−37.4%; −31.4%; −35.7%) scores. The CSI score had decreased by −29.0%, −21.4%, and −25.9%, respectively. In conclusion, after an intensive 3-day social cognitive intervention, treatment-resistant CP patients experienced substantial and lasting improvements in HRQoL and in problematic limitations to participation and autonomy, in association with improvements in pain attitudes, depression, and distress. To assess whether this innovative approach may be an effective treatment for this subgroup of CP patients, future randomized controlled studies are needed.