Upper left and lower left pain

Hi I have upper left pain which is between my shoulder and spine I get pain and cold sensation that travel down my arm to just above my elbow I also get pain in my lower left lower back near my buttocks and but cheek that goes into my hip. I have been to numerous chiro and pt had all MRI done i was told it was from tight muscles from poor posture and imbalance in muscle. Can having these issues affect one side of body I constantly use ice which helps but I often over use it and press very hard in where the pain is can I also be aggravating it more. I'm doing exercises to strengthen my upper and lower back. I do feel when I get stressed my muscles tighten and I feel worse.