What Is Causing A Dull Ache All Over One Side Of My Body?

since lasty night I have been experiencing an anchy feeling in the entire left side of my body - arms - legs- neck. Then all day today I have had chest pain just left of center, feels like some is pressing down on me, making it difficult to breathe as well. I haven't been able to sleep for years, two nights ago I increased the dosage of tylenol PM i have been taking for quite a while to help with sleep.