Moist heat. Get a large size towel sprinkle some water on it, put it in microwave for 3-4 minutes and use over the painful area, repeat 2-3 time. Good luck.
Sure. Warm shower or a bath can decrease muscular tension and spasms/cramps. Make sure you are well hydrated and consider a multi-vitamin as these can cause cramping. Green tea and other foods may lessen inflammatory processes. Plenty of sleep also will your body to naturally heal itself.
Many Things. Too many things to take a guess (prostatitis, urinary tract infection, true spinal back, pinched nerve, spinal stenosis, low potassium. Have your doc look into this. I know that on this forum you see the answer "see your doc" a lot. But we are here to give you basic clues and ideas, not to make the diagnosis. So see your doc is the right answer to follow most answers.
Back+Leg pain. A combination of back- and leg pain and cramps could be due to an acute disc herniation or another cause of nerve compression. Have yourself seen by a qualified doctor and maybe have an MRI outlining the nerves and your lumbar spine structures.... Good luck!
Back pain. This could be any one of a dozen things. The only way in which to investigate this is to be seen by a doctor, examined, have some labs and imaging studies done, all after providing a full history. Frankly this sounds very severe and should be looked into immediately. If you cannot see a family doctor now, go to an ER. Good luck.
Healthier living. Weight loss and exercise are important in managing chronic low back pain. Very difficult to do, but it is possible. Seeing a physical therapist and nutritionist maybe the first start. Your gola with exercise is to re-align your postural mechanics or posture. Capcaicin over the counter may be helpful, with nutrition and good sleep hygiene. See your doctor, there are options.
Core Exercises. Typically core strengthening exercises are the best to help relieve pressure and forces in the spine. I would try and google some or look them up on youtube to see descriptions. If you can do them yourself, wonderful otherwise ask your doctor to get a referral to a good physical therapist for further assistance.