Cases of medically unexplained arm pain pose a dilemma for general practitioners. The absence of observable physical pathology implies a psychosocial problem, but patients often insist that their illness is bio-mechanical. Should the doctor risk invalidating the patient's claims and damaging the doctor patient relationship, by insisting on a psycho-social explanation, or follow the patient's wishes and prescribe treatments which are likely to be ineffective? Findings from a qualitative study of 14 general practitioners in the South West of England are presented and discussed in the context of the sociology of suffering. The findings indicate a high degree of clinical uncertainty in dealing with non-specific arm pain cases and identify a range of strategies adopted to manage this uncertainty and the problems associated with it. Critics of 'bio-medicine' have argued that it focuses narrowly on physical pathology, while neglecting the patient's subjective beliefs and emotional needs. Our findings question this view, suggesting that GPs are often prepared to set aside the rigour of clinical science and the search for physical pathology in order to avoid invalidating the patient's claim that their illness is bio-mechanical rather than psycho-social. While this conforms to cultural expectations of what constitutes an appropriate response to human suffering, it may not be in the patient's best interests.