I've lived with chronic sinusitis for a decade now, and know what an utter nightmare if can be. It's very debilitating at times - I've had near-constant pain and every minor cold I catch (which, as a teacher working with small children, is many!) turns into a full-blown sinus infection. Even without the pain, the internal facial pressure causes a a constant 'woozy', feeling, a bit like swimming underwater, where nothing seems 'real' - obviously this isn't ideal when trying to work/carry out daily tasks! Sinusitis has also affected my eyesight, as the pressure in my face and eye area causes floaters and blurred vision (had it checked out by Moorfields and it's definitely nothing more sinister than the sinusitis, but they said there's very little they can do about it).
Have finally got my GP to refer me to an ENT specialist, after many instances of not being listened to. However, I'm not sure I'd opt for surgery, as I've heard from multiple sources (including several GPs) that it's quite a nasty procedure and the success rate isn't great. Probably not what you want to hear, I know, but that's the advice I've been given. Apparently it involves 'stripping' the sinuses of their natural lubricant, which leaves them quite 'raw' and can make breathing more painful. It's also fairly common for the operation to work temporarily, only to revert to normal after a year or so.
Part of the problem with sinusitis seems to be that it has so many different causes - structural problems within the sinuses themselves; allergies; untreated infections; excessive sensitivity to tiny changes in weather/ air pressure. Every sufferer will be different. In my case, I think it's at least partly hereditary/structural, as my mum has similar problems, which again went misdiagnosed for many years as migraines or eye problems.
For me, what has worked more than anything else is daily sinus rinsing using a neti pot. It's really very simple to do once you get the hang of it, and not very expensive - a tenner or so for the pot and some saline sachets. It's important to use sterile/distilled or boiled water to avoid the risk of infection, as untreated tap water has been linked to several deaths among neti pot users in the US. I also take antihistamines for allergies. I've tried steroid sprays, but they give me nosebleeds (apparently 15-20% of people are predisposed to this) and I do think you become dependent on them if used for long periods, which makes symptoms worse once you try to stop.
One other thing: I've noticed that holidays in places with dry or thin air (Spain, the Alps etc) have caused my symptoms to ease dramatically. For example, I've just been skiing, and was pretty much symptom free for the whole week (bliss!). For this reason, I've recently bought a dehumidifier, as our air here in the UK is naturally very moist, plus I live in London which obviously has higher pollutant levels than elsewhere. It's early days yet, but it does seem to be having a positive affect on my symptoms - less facial pressure etc. However, your mum really needs to work out what exactly it is that affects her, as equally some cases of sinusitis are eased by moist air (hence being told by GPs to inhale steam etc!). Personally whenever I did this or used a steam room my symptoms would ease briefly, then come back with a vengeance, so it seems drier air is the way to go.
Re. the ears, I do sometimes have pressure/pain here too, and I don't think it's that unusual - obviously all of the 'tubes' in this area are interrelated, and a problem with one area can have a knock-on effect on another. If your mother's problems are caused by the structure of her sinuses themselves (as I suspect mine are) it may be that she has particularly narrow ear canals or Eustachian tubes. Mine are very narrow, and I need to have my ears syringed regularly to avoid a build-up of ear wax, which can cause more pressure and exacerbates my sinus problems.
Phew - apologies for the essay-length, but I've become something of an expert on this subject over the past ten years! Unfortunately the whole area seems to be little understood by GPs, and there seems to be a general attitude (among some, not all) that since it's not a life-threatening condition it's something that just has to be put up with. Just let me know if there's anything you'd like to ask about your mum's condition - am more than happy to help where I can. Hope she gets the answers she needs soon!