1
general::
Phrase(s): on pins and needles
Fig. anxious; in suspense. • I’ve been on pins and needles all day, waiting for you to call with the news. • We were on pins and needles until we heard that your plane had landed safely.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Nervously anxious, as in He was on pins and needles, waiting for the test results. The graphic expression pins and needles for the tingling sensation experienced in recovering from numbness was transferred to a feeling of marked mental uneasiness about 1800.
American Heritage Idioms