It's possible you have an overlap of RA or Lupus, but it's not uncommon to have a lot of pain with Sjogren's. My pain isn't too bad, usually just my knees or hips, and occasionally I get the feeling that my skin is bruised and it's painful to the touch (from my neck to my knees). Once in a rare while I will wake up and feel like I have the flu or that I've been hit by a truck.
Sun sensitivity is common, I get a rash when I'm out in the sun or heat for an extended period of time. I started getting this in my late teens (I'm 29 now). Some medications can increase your sun sensitivity, too. It's recommended to wear sun-protective clothing, hats, and high-SPF sunblock.
Have you asked your doctor about a higher dose of prednisone? I'm not sure what your inflammation markers are like, but I was started on 60mg (due to my kidneys...another story) and it was like someone flipped a switch. I felt great! The only time I hurt was after a few days of no sleep and my body started giving out. I know no one loves being on prednisone (the jitteryness, weight gain, long-tern side effects), but maybe a higher dose is something to ask about.
A good resource (as well as another message forum) is sjogrensworld.org. There are links to articles as well as books on Sjogren's. I was able to find the books through my local library.
29 year old female (full-time accountant/part-time student)
Dx'd 2009: Primary Sjogren's Syndrome, distal RTA, bilateral nephrocalcinosis (calcium-oxalate), chronic interstitial nephritis, Stage 3 CKD, Raynaud's Phenomenon
Rx: Cellcept 1000mg 2x/d, Plaquenil 200mg 2x/d, Prednisone 20mg/d (tapering), Urocit-K 3mEq 3x/d, hydrochlorothiazide 12.5mg/d, potassium chloride 20mEq/d, Restasis, Numoisyn, Nystatin