Since these symptoms have only come on recently, it does seem very likely that they are linked to reduced activity levels during lockdown. Staying at home most of the time dramatically reduces the amount of time we are active – and it's not just that exercise classes aren't running. I think we forget how much movement we do throughout the day just by walking from A to B.
I really think in your instance it would be good to get moving a little more to see if it helps your symptoms. Due to your pain, I think the hardest part will be getting going but hopefully, once you do, you'll see improvements quickly.
It's great that you are doing Pilates but I would suggest adding in some more walking to your exercise regime as well, beginning with some shorter ones and then gradually adding more in. If you can do some cycling or even find an aerobic workout online, I think this would help too. If you need more ideas, I've put links to a couple of relevant blogs below.
• Easy ways to exercise at home
• Are you sitting too much? - find out the effects of a sedentary lifestyle, plus tips on how to move more throughout the day
• 10 motivational tips to stay active during lockdown
Other than this, it may help to increase your magnesium intake – it's very good for the muscles and joints. Having a hot bath regularly may also help to subdue the pain. However, if it persists, don't be afraid to contact your doctor or a physiotherapist for further advice.