How Should Breast Development Due To Gynaecomastia Be Treated?

i a m a 23 year old male, i have been doing bodybuilding for 4 years, but for the past 1 year i hav`nt done any kind of exercise.
now i have developed small brests, like in the case of gynaecomastia, i have thought of using testesterone injections. please guide me in this refernce