The phrase "feels concern" is a common expression to describe one's worries or apprehensions towards a particular situation. However, there are several synonyms that can be used to convey the same sentiment. "Frets," "agonizes," "broods," and "worries" all imply a sense of unease or distress. "Cares," "minds," "sympathizes," and "empathizes" suggest a desire to help or alleviate the situation. "Is troubled," "is anxious," and "is apprehensive" describe a state of worry or nervousness. By using these various synonyms, one can more accurately and effectively communicate their emotional response to a given situation.