Yes. Please get an endocrinologist consult.
Yes it could be. You could have a low level of testosterone. At your young age, you certainly need to have this checked by your family doctor asap.
It's possible. Gynecomastia with low levels of energy and small genitalia could indicate a low level of testosterone. An endocrinologist could help you determine if that is the cause. Gynecomastia is usually trusted by a plastic surgeon once other medically treatable causes are ruled out.
I have a small penis, gynecomastia, always tired, retain a lot of liquid. Will go to an endocrinologist... What should I tell him and ask?
Just that question.. Endos deal with that kind of thing all day. Start with that and the endo will take it from there. They are very smart.
Everything. Tell him/her about your development during puberty. Any meds you take, drugs you use or used. Family history. Mention any other symptoms.