<s>[INST] I have a squishy lump on my ribcage left side when i touch it it turns. My left arm. Numb and caused my heart to feel stabbing pains i went to er they did an xray to make sure my ribs werent out of place but the pain in chest left and arm numbness left. I comes back when i put my arm at my side its scares me what can ithis be [/INST] Thanks for your question on Chat Doctor. I can understand your situation and problem. In my opinion, we should first rule out heart related diseases because they are common cause for left sided chest pain with left arm numbness. So first get done ECG and 2d echo. If both are normal then no need to worry about heart diseases. Possibility of musculoskeletal pain is more in your case. So avoid movements causing pain. Avoid bad postures in sleep. Avoid heavyweight lifting and strenuous exercise like. Take painkiller and muscle relaxant Chat Doctor.  Apply warm water pad on affected areas. Don't worry, you will be alright. Hope I have solved your query. Wish you good health. Thanks. </s>