Patients with forked sensation under the left side of the ribs may be caused by excessive stretching of the intercostal muscles during strenuous exercise, which may cause tension or spasm of the intercostal muscles, resulting in the symptoms of pain under the left side of the ribs. In addition, you can take oral anti-inflammatory and analgesic drugs, such as diclofenac sodium, to relieve the pain. You can apply heat to the painful area to promote local blood circulation, relieve muscle spasm and relieve the painful symptoms. There is also a possibility that the left side of the subcostal pain may be suffering from intercostal neuritis. This situation also requires symptomatic treatment with painkillers, and can be treated with nerve-nourishing drugs, if the symptoms still do not improve further tests are needed to clarify the diagnosis.