Hi I'm 20 I Have Pain In Left Side In

Hi I'm 20 I have pain in left side in my back from 6 months & I'm experiencing that my poop as well having holes I smoke a lot of cigarettes as well I don't know what it is is it any type of cancer i almost got a great attack likes feeling when I got crams in my chest as well plz suggest what should I do I'm becoming very weak as well I do a call center job at night so my sleep timings varies plx help