What would abdominal symptoms be with lymphoma.. would it cause just a mild pressure or more like a pain, and would other symptoms be present as well? could it go on unchanged for many months or would the symptoms get worse? please help?

Most lymphomas I've seen that have abdominal involvement have had predominantly systemic symptoms like fever,sweats,weight loss rather than mechanical symptoms but pain,vomiting,constipation, appetite loss certainly can occur especially if a mass is large enough. Some lymphomas types are rather indolent and worsen very slowly over months or years even if untreated.