Ultrasound:Solitary lymph node submental region. There for 2 weeks. No other symptoms. A little soft on touch. Smoker. How long before it goes away? Cancer?

Might not. I'm not sure what you mean by "soft on touch". Being a smoker, I'm sure this is worrisome; however, an ultrasound (or CT scan) gives only limited information. It may be a scar from a prior infection (viral bronchitis), or a lymph node from existing infection, or cancer. The only way to tell is to perform a biopsy. Subsegmental means it may be too far away for bronchoscopy or CT-guided biopsy. TTYD.