The song is in the first person, "I". First you view it literally: "I was bruised and battered etc" Well, Bruce may have had a fight at some point in Philly, and this is his description of it - and Bruce is great at this kind of personal, emotional description ("I took month-long vacations in the stratosphere etc"). And his metaphores ("month-long vacations") usually relate pretty directly to real experiences, rather than being a metaphore for space travel or any of those things that english teachers like to dredge up.
Therefore, there's a pretty good argument for Bruce taking an experience of his own that had nothing to do with being gay, and realizing that a lot of people who aren't Bruce have a resonance with his song-feelings he used that to encompass the theme of the movie. Relating the experience of the movie dudes to the larger world - most of us aren't gay men dying of AIDS in Philly, but we can feel some of that thru his song.
Second, you use that "I" in another sense, he was putting himself in the place of the movie dudes, and seeing what it felt like to walk the streets in that condition. For example, the dude in "Born in the USA" isn't him, but he does a good job of imagining and then putting voice to that person.
Third, there is the sense of the universal "I". If one person experiences something, then because we are all connected in the universe we are all experiencing it. Bruce isn't totally into the new age mysticism, but month-long vacations in the stratosphere do tend to awaken the mystic in any of us. SO, from that point of view, the song is about all of us and our pain, and how we are connected, and if one of us is in pain in Philly, then all of us are, somehow.
Fourth, the cynical view that "I" is an artistic device that Bruce uses often (and skillfully) to hook the listening audience into his stories. Compare with other Bruce "I" songs - Jungleland, Born in USA, etc.
Fifth is the generally held view (I've certainly heard it a lot) that he started writing this when a friend died, and felt that it was appropriate for the movie.
And lastly, I've heard some people of a sexual persuasion other than mine say that it's Bruce's way of telling the world that he himself was really gay, and that it is the way he feels in real life because the "real" part of him, his gayness, has to be hidden but that it is causing him this much pain and it's killing him. I've never met Mr. Springstein, but I think if he's hiding his "gayness", he's doing a great job and having a lot of fun in the process, so I'd take this with a grain of salt. However, it is interesting to go back over some of his best songs and re-interpret them from the point of view of a guy who's really gay trying too hard to make it in the heterosexual world. "Under the Boardwalk" etc becomes very different when looked at that way, for example.
(I'd take all this with a grain of salt - you can equally look at it from the point of view that Bruce secretly wanted to be a terrorist and he's scouting under the boardwalk for bomb placement sites, and that Streets of Philly is what happens afterwards - and NO, I'm not comparing being gay to being a terrorist, it's a literary fantasy. Works equally well with Bruce secretly wanting to be a paleontolgist, looking for fossils under the boardwalk; the pain of extinction, etc)
In other words, it is easy to stretch the "meaning" of a song into almost anything you want. In Bruce's case, it probably isn't a good idea.
Bruce is more known for his directness than for subtle meanings.
Good luck with your paper.
Facebook
Twitter