I have what I thought was a cyst but now its all red and a little sore could it be a boil?

Possibly Yes. What part of body? Is it around a hair follicle? Do you have any insect bites? Is redness spearing? Is it worm, tender or has an area of fluctuation? Most likely you are right. Keep an eye on it. Maintain personal hyegiene. Do not scarch with bare hands or use any irritants or soap. It OK to use OTC antiseptic & if needed topical antibiotics.
Abscess. Absolutely! Or the cyst could have become infected. You should see a physician as soon as possible to limit worsening of the condition. You may require incision and drainage and/or antibiotic treatment. Good luck!