I've done a good job, I'm looking good, I've achieved something special - why would someone telling me so make me feel uncomfortable? It's not humility; I can believe the praise is valid. It's because praise is judgement, the sunny side of judgement but still judgement. Someone has appraised my performance and found it pleasing. If I receive their positive appraisal, it feels like I've given them permission to also appraise me negatively. This makes me feel vulnerable, hence uncomfortable.
What can be done? I have no control over other people's behaviour but I have become more aware of my own. Rather than give praise, I'm trying instead to make an observation, speak about how I was affected. 'Your work has given me a good idea.' 'I enjoyed watching what you did.' 'I can now see how this is useful.' I try to witness rather than judge. And hopefully connect more meaningfully.