What Causes Severe Pain In Arm With Swelling In Fingers While Stretching?

i broke my radial head bone back in early march i was in plaster for a total of 8 weeks i now have a half plaster on to which i dont wear all the time only when needed . i cant rotate my arm at all or stretch out i have constant pains and aches all the time that are getting worse and very often my whole arm including my fingers swell up making the pain intense