You asked a similar question the other day regarding Lown-Ganong-Levine syndrome for which I responded. Below, you will find the link to my response...
http://www.medhelp.org/posts/show/751268?personal_page_id=399635&post_id=post_3945425
"Could stomach ulcers cause stomach pain, or high cholesterol??" Ulcers can cause stomach pain but has nothing to do with your cholesterol, meaning high cholesterol will not cause pain in your stomach.
In regard to your extremely high cholesterol, I suggest that if your Dr hasn't prescribed a cholesterol lowering medication, you should advocate for yourself and ask him about you starting on it.
I, and other respondents on this Community, are in general not Doctors. Some have considerable related professional experience, but all are responding as individuals/patients who are sharing what their experiences have provided them.
Not being a doctore, I do not know what "LGL" stands for, you may get some more input if your spell it out.
A total cholesterol reading over 300 is very troublesome, didn't your doctor prescribe a statin drug? Generic drugs such as Simvastatin are very inexpensive, even in the US where one without any insurance would have to purchase out-of-pocket. So, unless you have a problem with statin meds, it should help a lot with your cholesterol problem.