Hello, and thanks for writing in.
Overall, unfortunately, I can't tell you specifically what is causing Kobe's issues that you are describing (without actually examining him), but I will try to speculate a bit, knowing what commonly causes problems like this in dogs that are Kobe's age.
In general, lumps fall into four main categories:
--tumor (benign or malignant),
--cyst (fluid-filled structure),
--abscess (infection-filled structure),
--granuloma (firm area of inflammation).
The only way to find out is to have a veterinarian do a needle aspirate of the lumps and look at the sample under a microscope to try and get a better idea of what the lumps are. The other (better) way is to biopsy the lumps and send it to a pathologist where they can tell exactly what is going on.
It's possible that the lumps are fatty deposits that are common in older dogs in this area of their body.
The breathing issues and stopping while walking can go along with an underlying heart or respiratory issue (i.e. heart murmur, fluid in the lungs or chest, enlarged heart, tumor, bronchitis, heartworm disease, pneumonia). With these symptoms, I would highly recommend an exam, and possibly tests, such as a chest X-ray, heartworm test, and white blood cell count, in order to determine the best course of action to help Kobe.
I hope this helps.