This definitely sounds like colic issues. I've a hub on colic, https://hubpages.com/health/What-to-do-When-Your-B... and if she's stretching like this, she's trying to get relief from her gas pains. Try laying her down on her back while she's stretching, putting your hands under the soles of her feet and pushing against her... then, when you have a good tension going push her feet into a "peddling a bicycle motion," for 5-10 minutes. After that, move her into a position of being flat on her stomach and rubbing her back for 5-10 minutes, then try burping her again. If she continues to do this, I would definitely bring it up at her next pediatric appointment, in case the doctor has some further insight on this. He'll probably say it's colic, so make sure you tell him the remedies you've been using for colic, letting him know that there could be something more to it. He may want to switch her formula to something else, too, so be prepared for that.
Furthermore, I'm not sure who told you to ignore her when she does this, but I wouldn't listen to their child-rearing advice anymore. I don't mean to be harsh, but *anything* your two-month old baby is doing needs to be addressed and needs your concern and attention. A two-month old baby doesn't know how to "get your attention" in the way that they're saying, as manipulative as infants may seem, they cannot do this. Hell, a two-month old child shouldn't *have* to do this, they should be getting constant attention.