I'm fully vaccinated (sinovac), it's my 49 days here in hotel where i'm isolated, pcr test is always positive 5 times. i'm coughing sometimes without phlegm and mild lower back pain. i need to get negative result to be able to work abroad. help pls?

Most likely you have recovered from COVID 19 and the PCR test is detecting non viable virus. The cough though is now a chronic cough and further evaluation by a PCP is indicated. You may have a secondary infection or bronchospasm. If you have an antigen test, this may be a better screening test. See CDC guidelines and please discuss with your provider. Monitor temperature and breathing.

They shouldn't isolate you based on positive PCR and cough. I had patients with + PCR more than 2 months in the past. In patients with severe pulmonary disease on ventilators, the Covid-19 virus culture may be still positive up to 3 weeks; otherwise, you are no longer a host (who can transmit the virus) after 14 days. Covid cough may persist months after the infection. You should be off isolation.