xrays and link to symptoms is always difficult. don't always correlate. agree that right SIJ looks wider but seems you may be rotated to the camerea, and so the beam shoots down it at differnet angle therefore looks wider - like viola - i am not a radiologist.
think the advice before is what to try, make sure you have been assessed and treated by physio etc exeprienced in SIJ dysfunctions - give conservative rehab exercises a go, if fail then prolotherapy good option to try.

check out this presentation from John, who I worked with at Bupa Wellness in the UK - havent read it but searched for it and will give some information, search him out and see him for advice

http://www.bimm.org.uk/uploads/publi...olotherapy.pdf

good luck- say hi to him from me