Friend, there are many different types of lumps that affect the skin in dogs. Could this be related to the vaccines? Yes, there are times where there could be a localized inflammation where the vaccine was given; this generally is not malignant and will disappear within a month or so. Or, this could be something unrelated to the vaccine like a lipoma, a cyst, etc. I would have her checked by family vet, they will know where they gave the vaccine and if this is consistent with a vaccine induced granuloma.
If your vet finds that this is not related to the vaccine I would recommend you speak to your family veterinarian about doing an FNA (fine needle aspirate); this is a very quick test where your vet will collect a sample of the cells with a needle. Requires no anesthesia, inexpensive when compared to a biopsy and can be done within minutes during an office examination. Your vet will most likely submit sample to a lab to be evaluated under the microscope for a definitive diagnosis. The decision of benign neglect or complete surgical removal should be made based on FNA results.
As far as the lameness, I don't believe this is related to the vaccine. There are many different causes for a lameness. Common causes are a soft tissue (muscle, tendon or ligament) injury, arthritis, etc. to name a few causes. Upon rechecking the lump with family vet I would have family vet perform an orthopedic examination. In addition, discuss with your vet about a trial with an anti inflammatory medication like rimadyl. In the meantime rest her, no running or jumping; activity should be limited to urinate and defecate on a leash.
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