The lump you are describing need to be examined by a doctor to make the confirmation if any thing serious is there. Normally the lump on the chest on the pect region is mainly because of increase in the size of breast tissues in the male boy which is called as gynaecomastia
. This can be because of some hormonal
disbalance and it need to be corrected in the intial stage otherwise surgery has to be done.
I would suggest you to consult some doctor and after examination only it can be confirmed wether this is enlargment of breast tissue only or something else.
Thanks and take care.