Beyond the idea of adding an anti-biotic, more about that in a bit, I would also pay particular attention to the location you had the pump in place. Likely, it was located at a more major movement point. Meaning you were irritating it each time you moved. Maybe a bit too close to the end of the muscle or at a point where the muscle moves a bit more than you realized? Not every location will work for everyone, and depending on your normal muscle movements, you may have specific areas that will cause you more inflammation than others. As in if your daily routine means moving your arm in a specific set of movements all the time, think production line type of work, or even desk work if you are constantly shuffling paper from one stack to another etc.. anyway, I am sure you can figure out that sort of thing if you just think about it a bit.
Now, as to anti-biotics. They should be your last resort, not your first. I personally have already had to deal with 4 different versions of MRSA type infections. These were definitely caused by hospitalization, but the problem becomes more and more severe with each infection and each type of infection, making you possibly, and me particularly, more susceptible to more infections that are Multi resistant to the various anti-biotics available. If you can increase your vitamin C intake it will likely help your body more naturally take care of minor infections. You SHOULD research taking vitamin c a bit, before just purchasing the cheapest you can find somewhere. A large part of the available vitamins on the market make more claims than facts, and the actual versions of the vitamins, while they sound like more is inside, are actually created using chemical compositions that make it more difficult for your body to utilize. Just something to be aware of, and taking antibiotics for everything is actually bad for your general health, UNLESS absolutely required. If you do get antibiotic prescription, follow it exactly, and FINISH it completely. You may think the infection is gone, but if you do not finish the prescription as directed, you end up with a bit of the infection still left alive, that can easily mutate and become resistant to future attempts to kill it. This I know from experience, and believe me, it is NOT something you want to have to live with.
Sorry for the long post, but it is something that I have learned painfully, and do not wish anyone to have to live through if it is possible to prevent it.