I fed DC1 for 18 months no issues. Now feeding 8 week old DC2. My left breast particularly has started aching and occasionally I get quite sickening shooting pains. However I can feel no lumps, I'm not especially engorged and continue to feed regularly from that breast. No red or warm patches. I don't feel ill. No nipple pain or pain when feeding. Shooting pains seem to be random cam be close to a feed or a while after.
DC2 was suspected to possibly have thrush and he was given treatment but I wasn't. I didn't have any issues at the time but don't think I have thrush symptoms from what I've read. I did feed in bed last night but with DC1 in with us too, so rather than moving DC2 to switch sides I kind if laid almost in my front to allow him to feed from my left breast while he laid on my right side (in order to keep myself between him and the toddler who is 2. So I could have squished it a bit?! 
Should have called docs today but thought it would ease. Not sure what they'd do anyway.