Hi,
Thanks for asking the query,
Bleeding gums is usually due to gingvitis which is associated with many factors,like plague and calculus deposition, poor
oral hygiene, nutritional deficiencies, endrocrine changes like
pregnancy, puberty, systemic conditions like diabetes and leukemia.
Bump behind the teeth can be because of
vitamin deficiency, tobacco use, smoking, low immunity, leukemia, bacterial and viral infections.
Infected tooth may also drain abscess in the gums forming a lump.
A direct examination by a qualified doctor is necessary to narrow down the possibilities.
I suggest you to
consult a Dentist and get the examination done and if necessary get x-ray done .
Hope this helps out.
Regards.