Dear Not having fun,
Painful lovemaking and the soreness you describe can be the result of several physical situations. You mentioned being a relative newcomer to sex. The first few times you have intercourse, an unstretched hymen may cause pain. This may be the case especially if, as you say, your boyfriend's penis is on the large side. Additionally, the pain could be caused by too much sudden stretching of your vaginal walls. Sexual activity causes the vaginal walls to stretch, strengthen, and adapt over time to sexual activity. It may be that your body would prefer to gradually work up to the size of your boyfriend's penis. If you wanted to do this, you could use dildos, vibrators, or fingers that are a more comfortable size and see if the soreness goes away. If so, it may make sense to hold off on intercourse for awhile and try again if or when you work up to that size. There is a tremendous amount of variation between individuals in terms of how much stretching occurs and in terms of what depth and girth feel good.
There are other possible explanations for your soreness. You mention you use lots of lube, which certainly helps ease lovemaking pain. But it may be that the type of lube you are using is irritating your vaginal canal. Some lubes that contain glycerine or are scented, flavored, or contain cooling or heating properties often dry sticky or may burn a bit which could contribute to soreness. Try water-based lube without glycerine or a silicone-based lube and see if it helps. Experiment with lots of different kinds if it's fun to do so, just avoid petroleum and oil-based lubes and lotions because these break down latex condoms. And speaking of condoms, you may also have a latex allergy. Another option may be to try lambskin condoms and see if you feel less soreness after intercourse (though its good to note that lambskin condoms may be able to help prevent unintended pregnancy, but not reduce the risk of sexually transmitted infections).
It may also be possible that you have a vaginal infection which friction from intercourse causes to flare up. This infection could be bacterial or of the yeast variety. And one more consideration may be your sexual positions. Some positions may cause more soreness than others. If you use primarily one or two positions, try changing it up and see if that helps reduce pain.
If the pain is deep within the pelvis, it may be a sign of a more serious problem. The soreness you describe does not sound like you're having an internal problem. However, if this continues, it may be worth a visit to a health care provider, who will be able to rule out anything serious and may have some additional suggestions on how to make your lovemaking more pleasurable and less sore.Alice!