Regarding your CT chest, there are a few findings in the report. One is cardiomegaly which means that the heart has increased in size, this usually occurs due to the heart dilating over a period of time, this can develop in many patients who undergo chemotherapy as a result of the chemotherapy drugs or it can be unrelated to the bile duct cancer that the patient had in the past and is instead related to blockage of the arteries of the heart. This would be better understood by doing an echocardiogram or ultrasound of the heart so we can determine the exact cause.
The second finding is that the patient also had small nodules in the lung and the pleura, the pleura is a thin covering of the lungs. These nodules have been present for some time and this scan states that they have not changed their size or appearance since the past scan. Nodules which do not change their size do NOT require any treatment and they are less likely to cause any sort of chest pain either (There is an exception to this rule which ill mention at the end). These nodules are usually benign in nature and they could have been present for some time, most patients who are above the age of 60 will have one or two nodules due to exposure to the pollutants in our air or even due to genetic causes. However in this particular case, these nodules MUST be evaluated further a biopsy of one of the nodules should be done if not done already to make sure that they are TRULY benign in nature or not, the reason being that the past history of cancer does increase the chances of these nodules being malignant. Yes, most nodules are benign but with the past history of cancer, a biopsy would be recommended here especially the pleural nodules which have a higher chance of being malignant.
The third finding in the scan shows that there is a small amount of fluid which is present inside the pleural cavity, pleural effusion. The fluid in the pleural space can be due to various causes and in most patients, it is actually due to an infection or inflammation of the pleura. If this is the case then it would be treated well with antibiotics and steroids. ANother cause of this could be due to a problem in the organs underneath the lungs. The good news here is that the fluid has not increased in size since the last scan which means that the condition is not worsening. But the fluid should be removed and analyzed for the chances of it being due to any potential cancer.
Now usually steroids and antibiotics would help the pain which could be due to the effusion, however, if necessary the fluid can also be drained from the area with a needle guided via ultrasound. In addition, we can also treat this problem with a nerve block in the region which would provide pain relief as well.
Now regarding the cannabis, there are many options in that regard, YES it would work in managing pain associated with effusion or even pain associated nodules (which usually don't cause pain but even in those rare cases where pain does occur, it can be used). There are many types of cannabis however the best forms of use are either inhaled version of the cannabis or a tablet. Now basically the doses for the medical marijuana vary from patient to patient, the rule of thumb is to start with the lowest possible dose and gradually increase it until the best effect is achieved. Each patient responds slightly different doses. In most patients, the starting dose may be between 2.5-6 mg of medical marijuana (in oral form) per day and then that dose would be slowly increased. But to answer your question oral forms like oils, consumables along with vaporized marijuana are the most effective.
Lastly, I just got your last message, are you saying that they did a biopsy of the nodules and they were found to be cancerous?