If the patient has a vague pain under the left rib cage after inspiration, it is most likely related to the following conditions.
Firstly, it may be caused by muscle spasm, for example, if the patient is cold or has a poor posture, such as prolonged hunching, which may cause muscle spasm.
Secondly, it may be caused by an old injury, such as a previous old rib fracture, which may occur on cloudy days when it rains.