You may have left upper quadrant (LUQ) pain from conditions that affect organs like your spleen, kidney, or stomach. It is important to see a doctor if your LUQ pain worsens or lasts more than 48 ...

Back pain only on your lower left side may be a sign of an infection, muscle strain, kidney stones, or stress fracture.

Are you dealing with neck and upper back problems? I have personally dealt with all kinds of neck issues resulting in one surgery to fuse C6-7 (cervical spine/neck), and another one later C4-5, and C5 ...