Tracie and Chellybean are right. A cricket will not make that type of lumpy look sitting in the intesinal tract or stomach. As Tracie mentioned, It could be the angle his sitting at that is showing a rib bone. It's very hard to tell from your pic, it's a little to fuzzy to get a good look at. Watch to see if it shows at different angles, like when he's standing or walking. If you can see it all the time, then I would recommend a vet visit. The vet can feel the area and decide if there is possibly a cyst or mass there and can do xrays or even ultrasound to get a visual of it. The vet may also choose to biopsy it and have it tested. It is very likely nothing to worry about, but, if you can see this all the time or it begins to get larger, the vet is the best route. Masses in beardies are generally not a good thing. Now, you said he's eating and pooping normally and active, but, be aware that when a beardie has a more serious illness, you often don't see signs of illness or changes in eating and behavior until the illness has gotten really bad. Watch him closely for a day or two, see if you can see the lump when he's in different positions, see if it appears bigger in any way. And if your still concerned, call a herp vet.
Good Luck.