Can I Use Cortisone For Osteoarthritis, Heel Spurs And Plantar Fasciitis?

Hi. I m a 52 year old femaIe and I have osteoarthritis, heal spurs and plantar facitis. A triple wammy. I ve been wearing custom orthos daily and all day. What do you think about cortisone injection? Possibly allergic to Sulfa, waiting for med testing, so no anti-inflamatory. Advil every four hours. Dosen t work. Have done exercising and stretches, icing too. massages and golf ball. This will all work for a bit but then pain comes back. Very Painful in am and when sitting for a bit , then starting to walk again. Always uncomfortable. My feet are swelling up on a regular basis. Do i try cortisone, or wait for testing then meds. I m frustrated.