On most tires there is a line in the molding just above the rim. If you hold the wheel in your hands and spin it, that line should stay the same distance from the rim as the wheel turns. If that line jumps up or dives below the rim, well there is your issue. (Be sure to check both sides.) Deflate the tire part way, You may be able to massage the tire with your hand to ease a place where the line had dived back up (so the tire bead is properly sitting on the rim shelf). For bulges up, deflate the tire entirely and work the tire around the rim and reinflate. Partially inflate and check the line.
Your issue may be some thing else entirely but this is easy to check (and you want to get it at least close because the high portion popping off the rim means a blown tube that cannot be saved and sometimes tire damage.
Ben