"muscle spasm, caused by misalignment and my very slight scoleosis"
Typical diagnosis from a chiropractor. Gives adjustments, message and rest and ice.
Relief of pain will be temporary and then you will run back for the typical treatment again and again and again, fattening the wallet of the chiropractor, thinning your wallet and continuing to go round and round with no real diagnosis or treatment.
You say that standing and leaning over in a lab "which on an ordinary day causes considerable back pain."
That is not a normal thing to happen to you and should have been a red flag warning sign that something is not right with your spine and it needs to be evaluated by a medical doctor.
Repeated problems like you are having with your spine and now new symptoms that come on suddenly are all red flags that something is wrong.
You need to be thoroughly evaluated by a spine specialist. Either an orthopedic surgeon who specializes in spines or a neurosurgeon that specializes in spines only.
Sounds like you will need and MRI of your spine, possibly one of the lumbar, thoracic and cervical spine to help diagnose your spinal problems.
Forget about returning to the chiropractor, try some ice and ibuprofen to decrease inflammation. If you find no relief with ice, you can try moist heat.
Arrange to see a spinal specialist ASAP.
At the present time, the only thing you can do to relieve the pain is to not be standing and leaning over in a lab. It will cause the pain to increase for you.
You can try taking frequent breaks from the position you will be in, alternate between sitting and standing. It may help some.
What you really need to do is get to the spine specialist as fast as possible and get that diagnosis.
Good luck
Fran