Welcome to the community...I'm sorry to hear about your Amazon, but it doesn't necessarily mean anything life-threatening...
Have you had this growth checked by either a Certified Avian Vet or an Avian Specialist Vet, and had it biopsied? This is always going to be the first step, because very often soft growths on their bodies end-up being either some type of cyst that needs to be drained or left alone and watched to see if it continues to grow and start to cause issue,
OR they are often Fatty Tumors, which are usually benign and harmless and also just need to be watched for continued growth/changes, OR they are also often Abscesses from a localized infection, such as in a pore, a feather follicle, etc., and if this is the case they must be drained and Antibiotics given to clear the infection up. The 4th possibility is it being another type of tumor, which may or may not be malignant, but typically that's not the case...HOWEVER, you'll not know until you get your bird to a CAV or Avian Specialist for a diagnosis, which is going to be critical, AND THE SOONER THE BETTER WITH ANY TYPE OF GROWTH, BECAUSE IF IT IS ANYTHING "BAD", IT NEEDS TO BE CAUGHT EARLY...
***Typically, and very, very common to Amazons, is that these soft tumors that develop on their bodies are called "Lipomas", which are simply tumors made of fat, and that are typically growing right beneath the skin, and do not have any organ involvement and are typically benign. Amazon's are very prone to them, and they are usually harmless in the sense that they are no cancerous...
****Lipomas, however, are a sign of a serious and life-threatening disease called Fatty Liver Disease, so they are not actually "harmless", and once the Lipoma develops,
soon many others start to form all over the body. Lipomas are typically caused by a regular, daily diet high in fat, usually from an all-seed diet that includes sunflower seeds, safflower seeds, corn, and nuts, such as peanuts. Parrots that do not eat pellets as their "staple" diet, but rather a seed-mix that contains sunflower seeds, peanuts and other nuts, corn, etc. So once a Lipoma develops on your bird and it is diagnosed as being a Lipoma by a CAV, typically they'll also take blood and run routine blood-work to test their liver functions, and usually they get a diagnosis of having Fatty Liver Disease....And when this diagnosis is confirmed, the most important thing you need to do is to change the bird's diet from the unhealthy seed-mixes to hopefully a staple of pellets, with only a small supplementation of a HEALTHY SEED-MIX that does not contain sunflower seeds, no peanuts, no nuts at all, no corn, etc. And then also the incorporation of fresh veggies every single day, and a very small amount of fresh fruit only a couple of times a week, as all fruit contains a ton of sugar, which is turned into fat and stored in the liver as well...
What is your bird's daily diet?
