Problems with stomach since latest treatment

[XPDeus]

Lately when I've been running, most of the time I find that within the first few minutes my stomach swells (gas I think) and make me very uncomfortable. My prostate was removed 3 years ago, I had radiotherapy and hormone therapy to follow. Since my latest treatment in January - sabre radiotherapy on a lymph node this has been happening. Has anyone else experienced this ?

[treedown]

Nothing like it related to radiated lymphnodes that I am aware of. I am pretty sure it has to do with specific vegetables I eat, especially brussel sprouts. I do have swelling in my left calve from sitting at work. My cycling works that out after about 1 hr.