If you typed your request with both hands, your arm is not broken! Strains can vary in intensity from a dull ache to agonising pain, and as the previous answer advises, the best thing to do is present yourself at your local A & E Department, and get an expert opinion. An initial diagnosis may confirm a strain, without the need for an X-ray, but don't risk leaving an injury, complications can cause ireversable samage..
If in any doubt, go to your local hospital. I functioned with a broken wrist for two weeks when I was 11, so you can still do stuff (no-one believed the pain - scarred for life!!) Seriously, the NHS is still free and it's worth the wait to get it sorted out.