Translation:Is it your boyfriend who is kissing you?
No, not really; not necessarily.
The Subject Participle -(y)An, as an adjective, does not specify the tense. It could either be present or past.
For the future -(y)AcAk is used.
Specifically denoting the past is -mIş olan: "Her kitaptaki bilginin kaynağı, o kitabı yazmış olan yazarın zihnidir."