Background: It is well established that catastrophic thinking about pain modulates clinical pain severity, but it may also relate to interindividual differences in the pain experience during procedures. This mixed-methods study investigated the relationship between ratings of situational pain catastrophizing and reported pain sensitivity in the context of receiving a nerve block without sedation, and explored participants' experiences., Methods: Healthy volunteers (n = 42) completed baseline psychosocial questionnaires, underwent quantitative sensory testing, and received a lower extremity nerve block, followed by further psychosocial assessment and interviews. Associations of catastrophizing scores with pain sensitivity and procedural site pain were assessed using Spearman's correlations. Interviews were reviewed using an immersion/crystallization approach to identify emergent themes., Results: Greater situational catastrophizing scores were associated with higher pain sensitivity, measured as lower pain threshold and tolerance. Although females exhibited greater pain sensitivity generally, moderation analysis revealed a significant association between situational catastrophizing scores and pain sensitivity only among male participants. Qualitative interviews revealed the importance of participants' emotional responses to pain, and a mismatch of expectation and experience with procedural pain. Males also reported more negative comments about procedural pain., Discussion: Examination of the variable subjective experience while receiving a nerve block in this experimental lab-based study revealed an important relationship between situational pain catastrophizing scores and pain sensitivity, which was more prominent among male participants. These findings reinforce how insight into individual expectations, emotions, and thought processes may impact pain sensitivity during procedures, and may inform strategies to personalize care, improving patient satisfaction and procedural acceptance., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)