18 Months Ago I Noticed A Small Soft (nickel Sized)

18 months ago I noticed a small soft (nickel sized) lump about 3 inches above "heel" part of hand on arm. thought it was from wrist watch, then week or two later same thing on other arm. Soon after small lump grew on outer ankle joint then same on other ankle. They are about size of 1/2 egg. Now I am finding them just above inner elbow on both arms closest to body, pea sized and 2-3 in a bunch. Also rapid weight gain,from size 4 jeans to size 14. large masses here and there upper arms and soft blobs inside below knee. what on earth is going on??