别扭 has three common uses: (1) physically uncomfortable — 坐着别扭; (2) emotionally awkward or uneasy — 心里别扭; (3) at odds with someone — 闹别扭 (to have a falling out). The phrase 闹别扭 is especially common.
mistakes
Note the special pronunciation: bièniu, not biéniǔ. The second syllable is in neutral tone.