Antonyms for the phrase "pain in the neck" could be terms like "pleasure," "delight," or "comfort." A person or situation that brings joy and ease could be considered an antonym to the negative connotations associated with the phrase. Other words that could be used include calm, soothing, peaceful or relaxing. However, sometimes the antidote to pain can be perceived as simply being free from it, and in this case, "nothing" or "neutral" could also act as an antonym. Overall, using positive and uplifting language can help deflect the negativity that arises from the phrase "pain in the neck.