I recently had sciatica, and it sounds exactly like what your boyfriend is going through.
the doctor made me stretch it out for a while, and gave me anti -inflammatories (ibuprofen, asprin, motrin, etc) to take. Stretching it made the difference.
If he is literally unable to stand the stretching, then he needs to see a doctor.
also, could be muscle spasms, give him gatorade, and make him eat bananas lol.
-Jordan
Sounds like Sciatica which is pressure on the sciatic nerve, it takes its time but it will go , some theorys think its caused by a virus,Take some Ibebrufen painkillers , they will help, go to the Doc if you need stronger,meds and to get it checkled out, he wont die of it but it does hurt a lot. Rest and more rest.
Sounds like he has pulled a back muscle. Or strained it. Keep alternating warm water packs..you can even use a ziploc baggie. Use for 10 -15 min. Then use a cold compress..(Ziploc bag if needed.)
If he is neausiated, that is normal with back pain/injury. As well as the pain shooting down his leg. My back was out for over 1 week.
Only way to tell if he is in real bad shape is........CALL THE AMBULANCE!
Tell him it's for his own good. Period.
Good luck,
Snooze